Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6

Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6

[Swabey, Matthew A]

Odroid-C2 solid green screen on echo c > /proc/sysrq-trigger on Arch Linux mainline 4.16/4.17rc6
Using lightdm on xorg fb. No mali, utgard or odroid specific framebuffers. However it seems to happen on them too.

Steps to reproduce:
1. Boot
2. Echo c > /proc/sysrq-trigger with watchdog set. Or trigger the watchdog another way, i.e. watchdogd or system.
3. Watchdog causes reboot
4. Boots with screen solid green, see photo here: https://photos.app.goo.gl/9VyiweNAIMD07VSM2
	a. No error messages visible, see attached log file bundles containing dmesg, journalctl, package list, Xorg.0.log
	b. Linux-aarch64 is 4.16
	c. Linux-aarch64-rc is 4.17rc6
5. Reboot - screen back to normal and working

Thought - something about the way to trigger this reset isn't working, or a race condition is present which is being more reliably triggered? Perhaps in the dma controller or the HDMI?

Any help to track this bug down would be very helpful, or someone else who would be interested? I can't figure out where in the stack the problem is occurring, but I guess it is the bootloader.

Thanks,

Matthew

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Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6

[Neil Armstrong]

Hi,

On 25/05/2018 04:19, Swabey, Matthew A wrote:
> Odroid-C2 solid green screen on echo c > /proc/sysrq-trigger on Arch Linux mainline 4.16/4.17rc6
> Using lightdm on xorg fb. No mali, utgard or odroid specific framebuffers. However it seems to happen on them too.
> 
> Steps to reproduce:
> 1. Boot
> 2. Echo c > /proc/sysrq-trigger with watchdog set. Or trigger the watchdog another way, i.e. watchdogd or system.
> 3. Watchdog causes reboot
> 4. Boots with screen solid green, see photo here: https://photos.app.goo.gl/9VyiweNAIMD07VSM2
> 	a. No error messages visible, see attached log file bundles containing dmesg, journalctl, package list, Xorg.0.log
> 	b. Linux-aarch64 is 4.16
> 	c. Linux-aarch64-rc is 4.17rc6
> 5. Reboot - screen back to normal and working
Well, since screen goes back to normal means there is no bug on the kernel side.

This is caused by Amlogic's U-Boot.
The HW watchdog does a complete SoC reset, we cannot execute any code from kernel when the watchdog wakes up.

Please report this to Armbian and ask them to use Mainline U-Boot, this won't happen anymore.

Neil

> 
> Thought - something about the way to trigger this reset isn't working, or a race condition is present which is being more reliably triggered? Perhaps in the dma controller or the HDMI?
> 
> Any help to track this bug down would be very helpful, or someone else who would be interested? I can't figure out where in the stack the problem is occurring, but I guess it is the bootloader.
> 
> Thanks,
> 
> Matthew
> 
> 
> 
> _______________________________________________
> linux-amlogic mailing list
> linux-amlogic at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-amlogic
> 

Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6

[Swabey, Matthew A]

I just had a look at the Arch linux PKGBUILD for the uboot package I am using, and it is mainline 2017.07. So I am using the mainline uboot, just a bit older.

I?ll give Armbian a try ? is it the distro wit1h the most development so far? (Other than the 3.14.x releases which I would prefer not to use for now).

Matthew

Dr. Matthew Swabey - Director?
Bechtel Innovation Design Center - Purdue University
room: BIDC 225? ? ? phone: +1-765-494-8655

From: Tony McKahan [mailto:tonymckahan at gmail.com] 
Sent: Friday, May 25, 2018 3:46 PM
To: Neil Armstrong <narmstrong@baylibre.com>
Cc: Swabey, Matthew A <maswabey@purdue.edu>; linux-amlogic at lists.infradead.org
Subject: Re: Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6

Hello Neil, Matt,

Change to 2018.03 is in Armbian's development branch, just waiting to be rolled into the master.? I don't have this particular board for testing, but it should be updated soon.

On Fri, May 25, 2018, 3:57 AM Neil Armstrong <mailto:narmstrong@baylibre.com> wrote:
Hi,

On 25/05/2018 04:19, Swabey, Matthew A wrote:
> Odroid-C2 solid green screen on echo c > /proc/sysrq-trigger on Arch Linux mainline 4.16/4.17rc6
> Using lightdm on xorg fb. No mali, utgard or odroid specific framebuffers. However it seems to happen on them too.
> 
> Steps to reproduce:
> 1. Boot
> 2. Echo c > /proc/sysrq-trigger with watchdog set. Or trigger the watchdog another way, i.e. watchdogd or system.
> 3. Watchdog causes reboot
> 4. Boots with screen solid green, see photo here: https://photos.app.goo.gl/9VyiweNAIMD07VSM2
>? ? ? ?a. No error messages visible, see attached log file bundles containing dmesg, journalctl, package list, Xorg.0.log
>? ? ? ?b. Linux-aarch64 is 4.16
>? ? ? ?c. Linux-aarch64-rc is 4.17rc6
> 5. Reboot - screen back to normal and working
Well, since screen goes back to normal means there is no bug on the kernel side.

This is caused by Amlogic's U-Boot.
The HW watchdog does a complete SoC reset, we cannot execute any code from kernel when the watchdog wakes up.

Please report this to Armbian and ask them to use Mainline U-Boot, this won't happen anymore.

Neil

> 
> Thought - something about the way to trigger this reset isn't working, or a race condition is present which is being more reliably triggered? Perhaps in the dma controller or the HDMI?
> 
> Any help to track this bug down would be very helpful, or someone else who would be interested? I can't figure out where in the stack the problem is occurring, but I guess it is the bootloader.
> 
> Thanks,
> 
> Matthew
> 
> 
> 
> _______________________________________________
> linux-amlogic mailing list
> mailto:linux-amlogic at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-amlogic
> 


_______________________________________________
linux-amlogic mailing list
mailto:linux-amlogic at lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-amlogic

Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6

[Swabey, Matthew A]

Can also confirm green screen on watchdog reboot from "echo c > /proc/sysrq-trigger" for Armbian 5.44 with linux-u-boot-odroidc2-next version 2018.03.

This is in addition to the Armbian bug where shutdown -r now doesn?t reboot the system, just either freezes or powers down. Supposed to be fixed on 2018.03 but not working for me.

Matthew

Dr. Matthew Swabey - Director?
Bechtel Innovation Design Center - Purdue University
room: BIDC 225? ? ? phone: +1-765-494-8655

-----Original Message-----
From: linux-amlogic [mailto:linux-amlogic-bounces at lists.infradead.org] On Behalf Of Swabey, Matthew A
Sent: Friday, May 25, 2018 10:37 PM
To: Tony McKahan <tonymckahan@gmail.com>; Neil Armstrong <narmstrong@baylibre.com>
Cc: linux-amlogic at lists.infradead.org
Subject: RE: Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6

I just had a look at the Arch linux PKGBUILD for the uboot package I am using, and it is mainline 2017.07. So I am using the mainline uboot, just a bit older.

I?ll give Armbian a try ? is it the distro wit1h the most development so far? (Other than the 3.14.x releases which I would prefer not to use for now).

Matthew

Dr. Matthew Swabey - Director
Bechtel Innovation Design Center - Purdue University
room: BIDC 225? ? ? phone: +1-765-494-8655

From: Tony McKahan [mailto:tonymckahan at gmail.com]
Sent: Friday, May 25, 2018 3:46 PM
To: Neil Armstrong <narmstrong@baylibre.com>
Cc: Swabey, Matthew A <maswabey@purdue.edu>; linux-amlogic at lists.infradead.org
Subject: Re: Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6

Hello Neil, Matt,

Change to 2018.03 is in Armbian's development branch, just waiting to be rolled into the master.? I don't have this particular board for testing, but it should be updated soon.

On Fri, May 25, 2018, 3:57 AM Neil Armstrong <mailto:narmstrong@baylibre.com> wrote:
Hi,

On 25/05/2018 04:19, Swabey, Matthew A wrote:
> Odroid-C2 solid green screen on echo c > /proc/sysrq-trigger on Arch 
> Linux mainline 4.16/4.17rc6 Using lightdm on xorg fb. No mali, utgard or odroid specific framebuffers. However it seems to happen on them too.
> 
> Steps to reproduce:
> 1. Boot
> 2. Echo c > /proc/sysrq-trigger with watchdog set. Or trigger the watchdog another way, i.e. watchdogd or system.
> 3. Watchdog causes reboot
> 4. Boots with screen solid green, see photo here: 
>https://photos.app.goo.gl/9VyiweNAIMD07VSM2
>? ? ? ?a. No error messages visible, see attached log file bundles 
>containing dmesg, journalctl, package list, Xorg.0.log
>? ? ? ?b. Linux-aarch64 is 4.16
>? ? ? ?c. Linux-aarch64-rc is 4.17rc6
> 5. Reboot - screen back to normal and working
Well, since screen goes back to normal means there is no bug on the kernel side.

This is caused by Amlogic's U-Boot.
The HW watchdog does a complete SoC reset, we cannot execute any code from kernel when the watchdog wakes up.

Please report this to Armbian and ask them to use Mainline U-Boot, this won't happen anymore.

Neil

> 
> Thought - something about the way to trigger this reset isn't working, or a race condition is present which is being more reliably triggered? Perhaps in the dma controller or the HDMI?
> 
> Any help to track this bug down would be very helpful, or someone else who would be interested? I can't figure out where in the stack the problem is occurring, but I guess it is the bootloader.
> 
> Thanks,
> 
> Matthew
> 
> 
> 
> _______________________________________________
> linux-amlogic mailing list
> mailto:linux-amlogic at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-amlogic
> 


_______________________________________________
linux-amlogic mailing list
mailto:linux-amlogic at lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-amlogic
_______________________________________________
linux-amlogic mailing list
linux-amlogic at lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-amlogic

Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6

[Neil Armstrong]

Hi,

I'm sorry to disappoint you, but with the HW watchdog, we *can't* execute any code from Linux when the watchdoog resets the system.
We could eventually add some code in U-Boot to disable the HDMI output, but U-boot is not the first code executed, you will still see the green screen.
You may need to contact Hardkernel to see if they can update the BL* binaries to include such reset.

Neil

On 26/05/2018 05:49, Swabey, Matthew A wrote:
> Can also confirm green screen on watchdog reboot from "echo c > /proc/sysrq-trigger" for Armbian 5.44 with linux-u-boot-odroidc2-next version 2018.03.
> 
> This is in addition to the Armbian bug where shutdown -r now doesn?t reboot the system, just either freezes or powers down. Supposed to be fixed on 2018.03 but not working for me.
> 
> Matthew
> 
> Dr. Matthew Swabey - Director?
> Bechtel Innovation Design Center - Purdue University
> room: BIDC 225? ? ? phone: +1-765-494-8655
> 
> -----Original Message-----
> From: linux-amlogic [mailto:linux-amlogic-bounces at lists.infradead.org] On Behalf Of Swabey, Matthew A
> Sent: Friday, May 25, 2018 10:37 PM
> To: Tony McKahan <tonymckahan@gmail.com>; Neil Armstrong <narmstrong@baylibre.com>
> Cc: linux-amlogic at lists.infradead.org
> Subject: RE: Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6
> 
> I just had a look at the Arch linux PKGBUILD for the uboot package I am using, and it is mainline 2017.07. So I am using the mainline uboot, just a bit older.
> 
> I?ll give Armbian a try ? is it the distro wit1h the most development so far? (Other than the 3.14.x releases which I would prefer not to use for now).
> 
> Matthew
> 
> Dr. Matthew Swabey - Director
> Bechtel Innovation Design Center - Purdue University
> room: BIDC 225? ? ? phone: +1-765-494-8655
> 
> From: Tony McKahan [mailto:tonymckahan at gmail.com]
> Sent: Friday, May 25, 2018 3:46 PM
> To: Neil Armstrong <narmstrong@baylibre.com>
> Cc: Swabey, Matthew A <maswabey@purdue.edu>; linux-amlogic at lists.infradead.org
> Subject: Re: Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6
> 
> Hello Neil, Matt,
> 
> Change to 2018.03 is in Armbian's development branch, just waiting to be rolled into the master.? I don't have this particular board for testing, but it should be updated soon.
> 
> On Fri, May 25, 2018, 3:57 AM Neil Armstrong <mailto:narmstrong@baylibre.com> wrote:
> Hi,
> 
> On 25/05/2018 04:19, Swabey, Matthew A wrote:
>> Odroid-C2 solid green screen on echo c > /proc/sysrq-trigger on Arch 
>> Linux mainline 4.16/4.17rc6 Using lightdm on xorg fb. No mali, utgard or odroid specific framebuffers. However it seems to happen on them too.
>>
>> Steps to reproduce:
>> 1. Boot
>> 2. Echo c > /proc/sysrq-trigger with watchdog set. Or trigger the watchdog another way, i.e. watchdogd or system.
>> 3. Watchdog causes reboot
>> 4. Boots with screen solid green, see photo here: 
>> https://photos.app.goo.gl/9VyiweNAIMD07VSM2
>> ? ? ? ?a. No error messages visible, see attached log file bundles 
>> containing dmesg, journalctl, package list, Xorg.0.log
>> ? ? ? ?b. Linux-aarch64 is 4.16
>> ? ? ? ?c. Linux-aarch64-rc is 4.17rc6
>> 5. Reboot - screen back to normal and working
> Well, since screen goes back to normal means there is no bug on the kernel side.
> 
> This is caused by Amlogic's U-Boot.
> The HW watchdog does a complete SoC reset, we cannot execute any code from kernel when the watchdog wakes up.
> 
> Please report this to Armbian and ask them to use Mainline U-Boot, this won't happen anymore.
> 
> Neil
> 
>>
>> Thought - something about the way to trigger this reset isn't working, or a race condition is present which is being more reliably triggered? Perhaps in the dma controller or the HDMI?
>>
>> Any help to track this bug down would be very helpful, or someone else who would be interested? I can't figure out where in the stack the problem is occurring, but I guess it is the bootloader.
>>
>> Thanks,
>>
>> Matthew
>>
>>
>>
>> _______________________________________________
>> linux-amlogic mailing list
>> mailto:linux-amlogic at lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
>>
> 
> 
> _______________________________________________
> linux-amlogic mailing list
> mailto:linux-amlogic at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-amlogic
> _______________________________________________
> linux-amlogic mailing list
> linux-amlogic at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-amlogic
> 

Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6

[Michał Zegan]

What about the *kernel* resetting at boot?

W dniu 26.05.2018 o?10:33, Neil Armstrong pisze:
> Hi,
> 
> I'm sorry to disappoint you, but with the HW watchdog, we *can't* execute any code from Linux when the watchdoog resets the system.
> We could eventually add some code in U-Boot to disable the HDMI output, but U-boot is not the first code executed, you will still see the green screen.
> You may need to contact Hardkernel to see if they can update the BL* binaries to include such reset.
> 
> Neil
> 
> On 26/05/2018 05:49, Swabey, Matthew A wrote:
>> Can also confirm green screen on watchdog reboot from "echo c > /proc/sysrq-trigger" for Armbian 5.44 with linux-u-boot-odroidc2-next version 2018.03.
>>
>> This is in addition to the Armbian bug where shutdown -r now doesn?t reboot the system, just either freezes or powers down. Supposed to be fixed on 2018.03 but not working for me.
>>
>> Matthew
>>
>> Dr. Matthew Swabey - Director?
>> Bechtel Innovation Design Center - Purdue University
>> room: BIDC 225? ? ? phone: +1-765-494-8655
>>
>> -----Original Message-----
>> From: linux-amlogic [mailto:linux-amlogic-bounces at lists.infradead.org] On Behalf Of Swabey, Matthew A
>> Sent: Friday, May 25, 2018 10:37 PM
>> To: Tony McKahan <tonymckahan@gmail.com>; Neil Armstrong <narmstrong@baylibre.com>
>> Cc: linux-amlogic at lists.infradead.org
>> Subject: RE: Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6
>>
>> I just had a look at the Arch linux PKGBUILD for the uboot package I am using, and it is mainline 2017.07. So I am using the mainline uboot, just a bit older.
>>
>> I?ll give Armbian a try ? is it the distro wit1h the most development so far? (Other than the 3.14.x releases which I would prefer not to use for now).
>>
>> Matthew
>>
>> Dr. Matthew Swabey - Director
>> Bechtel Innovation Design Center - Purdue University
>> room: BIDC 225? ? ? phone: +1-765-494-8655
>>
>> From: Tony McKahan [mailto:tonymckahan at gmail.com]
>> Sent: Friday, May 25, 2018 3:46 PM
>> To: Neil Armstrong <narmstrong@baylibre.com>
>> Cc: Swabey, Matthew A <maswabey@purdue.edu>; linux-amlogic at lists.infradead.org
>> Subject: Re: Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6
>>
>> Hello Neil, Matt,
>>
>> Change to 2018.03 is in Armbian's development branch, just waiting to be rolled into the master.? I don't have this particular board for testing, but it should be updated soon.
>>
>> On Fri, May 25, 2018, 3:57 AM Neil Armstrong <mailto:narmstrong@baylibre.com> wrote:
>> Hi,
>>
>> On 25/05/2018 04:19, Swabey, Matthew A wrote:
>>> Odroid-C2 solid green screen on echo c > /proc/sysrq-trigger on Arch 
>>> Linux mainline 4.16/4.17rc6 Using lightdm on xorg fb. No mali, utgard or odroid specific framebuffers. However it seems to happen on them too.
>>>
>>> Steps to reproduce:
>>> 1. Boot
>>> 2. Echo c > /proc/sysrq-trigger with watchdog set. Or trigger the watchdog another way, i.e. watchdogd or system.
>>> 3. Watchdog causes reboot
>>> 4. Boots with screen solid green, see photo here: 
>>> https://photos.app.goo.gl/9VyiweNAIMD07VSM2
>>> ? ? ? ?a. No error messages visible, see attached log file bundles 
>>> containing dmesg, journalctl, package list, Xorg.0.log
>>> ? ? ? ?b. Linux-aarch64 is 4.16
>>> ? ? ? ?c. Linux-aarch64-rc is 4.17rc6
>>> 5. Reboot - screen back to normal and working
>> Well, since screen goes back to normal means there is no bug on the kernel side.
>>
>> This is caused by Amlogic's U-Boot.
>> The HW watchdog does a complete SoC reset, we cannot execute any code from kernel when the watchdog wakes up.
>>
>> Please report this to Armbian and ask them to use Mainline U-Boot, this won't happen anymore.
>>
>> Neil
>>
>>>
>>> Thought - something about the way to trigger this reset isn't working, or a race condition is present which is being more reliably triggered? Perhaps in the dma controller or the HDMI?
>>>
>>> Any help to track this bug down would be very helpful, or someone else who would be interested? I can't figure out where in the stack the problem is occurring, but I guess it is the bootloader.
>>>
>>> Thanks,
>>>
>>> Matthew
>>>
>>>
>>>
>>> _______________________________________________
>>> linux-amlogic mailing list
>>> mailto:linux-amlogic at lists.infradead.org
>>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
>>>
>>
>>
>> _______________________________________________
>> linux-amlogic mailing list
>> mailto:linux-amlogic at lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
>> _______________________________________________
>> linux-amlogic mailing list
>> linux-amlogic at lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
>>
> 
> 
> _______________________________________________
> linux-amlogic mailing list
> linux-amlogic at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-amlogic
> 

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Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6

[Swabey, Matthew A]

Well, if it is triggered on watchdog reboot, but not normal power-on or reboot then it has to be either the firmware, u-boot or the kernel not reconfiguring something. 

I don't know what the difference is between a watchdog reset and a normal boot though which would cause the change. Any hints before I go digging with a JTAG adapter through the SCP or SoC registers? (Thinking of dumping and diff'ing to see what changed.)

Matt

Dr. Matthew Swabey - Director?
Bechtel Innovation Design Center - Purdue University
room: BIDC 225? ? ? phone: +1-765-494-8655

-----Original Message-----
From: Micha? Zegan [mailto:webczat_200 at poczta.onet.pl] 
Sent: Saturday, May 26, 2018 4:50 AM
To: Neil Armstrong <narmstrong@baylibre.com>; Swabey, Matthew A <maswabey@purdue.edu>; Tony McKahan <tonymckahan@gmail.com>
Cc: linux-amlogic at lists.infradead.org
Subject: Re: Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6

What about the *kernel* resetting at boot?

W dniu 26.05.2018 o?10:33, Neil Armstrong pisze:
> Hi,
> 
> I'm sorry to disappoint you, but with the HW watchdog, we *can't* execute any code from Linux when the watchdoog resets the system.
> We could eventually add some code in U-Boot to disable the HDMI output, but U-boot is not the first code executed, you will still see the green screen.
> You may need to contact Hardkernel to see if they can update the BL* binaries to include such reset.
> 
> Neil
> 
> On 26/05/2018 05:49, Swabey, Matthew A wrote:
>> Can also confirm green screen on watchdog reboot from "echo c > /proc/sysrq-trigger" for Armbian 5.44 with linux-u-boot-odroidc2-next version 2018.03.
>>
>> This is in addition to the Armbian bug where shutdown -r now doesn?t reboot the system, just either freezes or powers down. Supposed to be fixed on 2018.03 but not working for me.
>>
>> Matthew
>>
>> Dr. Matthew Swabey - Director
>> Bechtel Innovation Design Center - Purdue University
>> room: BIDC 225? ? ? phone: +1-765-494-8655
>>
>> -----Original Message-----
>> From: linux-amlogic 
>> [mailto:linux-amlogic-bounces at lists.infradead.org] On Behalf Of 
>> Swabey, Matthew A
>> Sent: Friday, May 25, 2018 10:37 PM
>> To: Tony McKahan <tonymckahan@gmail.com>; Neil Armstrong 
>> <narmstrong@baylibre.com>
>> Cc: linux-amlogic at lists.infradead.org
>> Subject: RE: Odroid-C2 solid green screen on "echo c > 
>> /proc/sysrq-trigger" on Arch 4.16/4.17rc6
>>
>> I just had a look at the Arch linux PKGBUILD for the uboot package I am using, and it is mainline 2017.07. So I am using the mainline uboot, just a bit older.
>>
>> I?ll give Armbian a try ? is it the distro wit1h the most development so far? (Other than the 3.14.x releases which I would prefer not to use for now).
>>
>> Matthew
>>
>> Dr. Matthew Swabey - Director
>> Bechtel Innovation Design Center - Purdue University
>> room: BIDC 225? ? ? phone: +1-765-494-8655
>>
>> From: Tony McKahan [mailto:tonymckahan at gmail.com]
>> Sent: Friday, May 25, 2018 3:46 PM
>> To: Neil Armstrong <narmstrong@baylibre.com>
>> Cc: Swabey, Matthew A <maswabey@purdue.edu>; 
>> linux-amlogic at lists.infradead.org
>> Subject: Re: Odroid-C2 solid green screen on "echo c > 
>> /proc/sysrq-trigger" on Arch 4.16/4.17rc6
>>
>> Hello Neil, Matt,
>>
>> Change to 2018.03 is in Armbian's development branch, just waiting to be rolled into the master.? I don't have this particular board for testing, but it should be updated soon.
>>
>> On Fri, May 25, 2018, 3:57 AM Neil Armstrong <mailto:narmstrong@baylibre.com> wrote:
>> Hi,
>>
>> On 25/05/2018 04:19, Swabey, Matthew A wrote:
>>> Odroid-C2 solid green screen on echo c > /proc/sysrq-trigger on Arch 
>>> Linux mainline 4.16/4.17rc6 Using lightdm on xorg fb. No mali, utgard or odroid specific framebuffers. However it seems to happen on them too.
>>>
>>> Steps to reproduce:
>>> 1. Boot
>>> 2. Echo c > /proc/sysrq-trigger with watchdog set. Or trigger the watchdog another way, i.e. watchdogd or system.
>>> 3. Watchdog causes reboot
>>> 4. Boots with screen solid green, see photo here: 
>>> https://photos.app.goo.gl/9VyiweNAIMD07VSM2
>>> ? ? ? ?a. No error messages visible, see attached log file bundles 
>>> containing dmesg, journalctl, package list, Xorg.0.log
>>> ? ? ? ?b. Linux-aarch64 is 4.16
>>> ? ? ? ?c. Linux-aarch64-rc is 4.17rc6 5. Reboot - screen back to 
>>> normal and working
>> Well, since screen goes back to normal means there is no bug on the kernel side.
>>
>> This is caused by Amlogic's U-Boot.
>> The HW watchdog does a complete SoC reset, we cannot execute any code from kernel when the watchdog wakes up.
>>
>> Please report this to Armbian and ask them to use Mainline U-Boot, this won't happen anymore.
>>
>> Neil
>>
>>>
>>> Thought - something about the way to trigger this reset isn't working, or a race condition is present which is being more reliably triggered? Perhaps in the dma controller or the HDMI?
>>>
>>> Any help to track this bug down would be very helpful, or someone else who would be interested? I can't figure out where in the stack the problem is occurring, but I guess it is the bootloader.
>>>
>>> Thanks,
>>>
>>> Matthew
>>>
>>>
>>>
>>> _______________________________________________
>>> linux-amlogic mailing list
>>> mailto:linux-amlogic at lists.infradead.org
>>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
>>>
>>
>>
>> _______________________________________________
>> linux-amlogic mailing list
>> mailto:linux-amlogic at lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
>> _______________________________________________
>> linux-amlogic mailing list
>> linux-amlogic at lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
>>
> 
> 
> _______________________________________________
> linux-amlogic mailing list
> linux-amlogic at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-amlogic
> 

Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6

[Swabey, Matthew A]

Well, as an update.

Using arch linux for arm, modified their PKGBUILD to build u-boot 2018.05 with no patches at all. Signed and wrote to SD-CARD as per usual. 

Green screen on echo c > /proc/sysrq-trigger after watchdog reset.
No green screen on shutdown -r

Temporary solution for me will be to play a "double reboot" game with a fingerprint file to see if it was shutdown cleanly or not.

Best,

Matthew

Dr. Matthew Swabey - Director?
Bechtel Innovation Design Center - Purdue University
room: BIDC 225? ? ? phone: +1-765-494-8655

-----Original Message-----
From: Micha? Zegan <webczat_200@poczta.onet.pl> 
Sent: Saturday, May 26, 2018 4:50 AM
To: Neil Armstrong <narmstrong@baylibre.com>; Swabey, Matthew A <maswabey@purdue.edu>; Tony McKahan <tonymckahan@gmail.com>
Cc: linux-amlogic at lists.infradead.org
Subject: Re: Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6

What about the *kernel* resetting at boot?

W dniu 26.05.2018 o?10:33, Neil Armstrong pisze:
> Hi,
> 
> I'm sorry to disappoint you, but with the HW watchdog, we *can't* execute any code from Linux when the watchdoog resets the system.
> We could eventually add some code in U-Boot to disable the HDMI output, but U-boot is not the first code executed, you will still see the green screen.
> You may need to contact Hardkernel to see if they can update the BL* binaries to include such reset.
> 
> Neil
> 
> On 26/05/2018 05:49, Swabey, Matthew A wrote:
>> Can also confirm green screen on watchdog reboot from "echo c > /proc/sysrq-trigger" for Armbian 5.44 with linux-u-boot-odroidc2-next version 2018.03.
>>
>> This is in addition to the Armbian bug where shutdown -r now doesn?t reboot the system, just either freezes or powers down. Supposed to be fixed on 2018.03 but not working for me.
>>
>> Matthew
>>
>> Dr. Matthew Swabey - Director
>> Bechtel Innovation Design Center - Purdue University
>> room: BIDC 225? ? ? phone: +1-765-494-8655
>>
>> -----Original Message-----
>> From: linux-amlogic 
>> [mailto:linux-amlogic-bounces at lists.infradead.org] On Behalf Of 
>> Swabey, Matthew A
>> Sent: Friday, May 25, 2018 10:37 PM
>> To: Tony McKahan <tonymckahan@gmail.com>; Neil Armstrong 
>> <narmstrong@baylibre.com>
>> Cc: linux-amlogic at lists.infradead.org
>> Subject: RE: Odroid-C2 solid green screen on "echo c > 
>> /proc/sysrq-trigger" on Arch 4.16/4.17rc6
>>
>> I just had a look at the Arch linux PKGBUILD for the uboot package I am using, and it is mainline 2017.07. So I am using the mainline uboot, just a bit older.
>>
>> I?ll give Armbian a try ? is it the distro wit1h the most development so far? (Other than the 3.14.x releases which I would prefer not to use for now).
>>
>> Matthew
>>
>> Dr. Matthew Swabey - Director
>> Bechtel Innovation Design Center - Purdue University
>> room: BIDC 225? ? ? phone: +1-765-494-8655
>>
>> From: Tony McKahan [mailto:tonymckahan at gmail.com]
>> Sent: Friday, May 25, 2018 3:46 PM
>> To: Neil Armstrong <narmstrong@baylibre.com>
>> Cc: Swabey, Matthew A <maswabey@purdue.edu>; 
>> linux-amlogic at lists.infradead.org
>> Subject: Re: Odroid-C2 solid green screen on "echo c > 
>> /proc/sysrq-trigger" on Arch 4.16/4.17rc6
>>
>> Hello Neil, Matt,
>>
>> Change to 2018.03 is in Armbian's development branch, just waiting to be rolled into the master.? I don't have this particular board for testing, but it should be updated soon.
>>
>> On Fri, May 25, 2018, 3:57 AM Neil Armstrong <mailto:narmstrong@baylibre.com> wrote:
>> Hi,
>>
>> On 25/05/2018 04:19, Swabey, Matthew A wrote:
>>> Odroid-C2 solid green screen on echo c > /proc/sysrq-trigger on Arch 
>>> Linux mainline 4.16/4.17rc6 Using lightdm on xorg fb. No mali, utgard or odroid specific framebuffers. However it seems to happen on them too.
>>>
>>> Steps to reproduce:
>>> 1. Boot
>>> 2. Echo c > /proc/sysrq-trigger with watchdog set. Or trigger the watchdog another way, i.e. watchdogd or system.
>>> 3. Watchdog causes reboot
>>> 4. Boots with screen solid green, see photo here: 
>>> https://photos.app.goo.gl/9VyiweNAIMD07VSM2
>>> ? ? ? ?a. No error messages visible, see attached log file bundles 
>>> containing dmesg, journalctl, package list, Xorg.0.log
>>> ? ? ? ?b. Linux-aarch64 is 4.16
>>> ? ? ? ?c. Linux-aarch64-rc is 4.17rc6 5. Reboot - screen back to 
>>> normal and working
>> Well, since screen goes back to normal means there is no bug on the kernel side.
>>
>> This is caused by Amlogic's U-Boot.
>> The HW watchdog does a complete SoC reset, we cannot execute any code from kernel when the watchdog wakes up.
>>
>> Please report this to Armbian and ask them to use Mainline U-Boot, this won't happen anymore.
>>
>> Neil
>>
>>>
>>> Thought - something about the way to trigger this reset isn't working, or a race condition is present which is being more reliably triggered? Perhaps in the dma controller or the HDMI?
>>>
>>> Any help to track this bug down would be very helpful, or someone else who would be interested? I can't figure out where in the stack the problem is occurring, but I guess it is the bootloader.
>>>
>>> Thanks,
>>>
>>> Matthew
>>>
>>>
>>>
>>> _______________________________________________
>>> linux-amlogic mailing list
>>> mailto:linux-amlogic at lists.infradead.org
>>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
>>>
>>
>>
>> _______________________________________________
>> linux-amlogic mailing list
>> mailto:linux-amlogic at lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
>> _______________________________________________
>> linux-amlogic mailing list
>> linux-amlogic at lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
>>
> 
> 
> _______________________________________________
> linux-amlogic mailing list
> linux-amlogic at lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-amlogic
> 

Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6

[Neil Armstrong]

Hi,

Having the watchdog to reset the board is an exceptional event, why would you bother fixing this ?

Neil

On 04/06/2018 23:22, Swabey, Matthew A wrote:
> Well, as an update.
> 
> Using arch linux for arm, modified their PKGBUILD to build u-boot 2018.05 with no patches at all. Signed and wrote to SD-CARD as per usual. 
> 
> Green screen on echo c > /proc/sysrq-trigger after watchdog reset.
> No green screen on shutdown -r
> 
> Temporary solution for me will be to play a "double reboot" game with a fingerprint file to see if it was shutdown cleanly or not.
> 
> Best,
> 
> Matthew
> 
> Dr. Matthew Swabey - Director?
> Bechtel Innovation Design Center - Purdue University
> room: BIDC 225? ? ? phone: +1-765-494-8655
> 
> -----Original Message-----
> From: Micha? Zegan <webczat_200@poczta.onet.pl> 
> Sent: Saturday, May 26, 2018 4:50 AM
> To: Neil Armstrong <narmstrong@baylibre.com>; Swabey, Matthew A <maswabey@purdue.edu>; Tony McKahan <tonymckahan@gmail.com>
> Cc: linux-amlogic at lists.infradead.org
> Subject: Re: Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6
> 
> What about the *kernel* resetting at boot?
> 
> W dniu 26.05.2018 o?10:33, Neil Armstrong pisze:
>> Hi,
>>
>> I'm sorry to disappoint you, but with the HW watchdog, we *can't* execute any code from Linux when the watchdoog resets the system.
>> We could eventually add some code in U-Boot to disable the HDMI output, but U-boot is not the first code executed, you will still see the green screen.
>> You may need to contact Hardkernel to see if they can update the BL* binaries to include such reset.
>>
>> Neil
>>
>> On 26/05/2018 05:49, Swabey, Matthew A wrote:
>>> Can also confirm green screen on watchdog reboot from "echo c > /proc/sysrq-trigger" for Armbian 5.44 with linux-u-boot-odroidc2-next version 2018.03.
>>>
>>> This is in addition to the Armbian bug where shutdown -r now doesn?t reboot the system, just either freezes or powers down. Supposed to be fixed on 2018.03 but not working for me.
>>>
>>> Matthew
>>>
>>> Dr. Matthew Swabey - Director
>>> Bechtel Innovation Design Center - Purdue University
>>> room: BIDC 225? ? ? phone: +1-765-494-8655
>>>
>>> -----Original Message-----
>>> From: linux-amlogic 
>>> [mailto:linux-amlogic-bounces at lists.infradead.org] On Behalf Of 
>>> Swabey, Matthew A
>>> Sent: Friday, May 25, 2018 10:37 PM
>>> To: Tony McKahan <tonymckahan@gmail.com>; Neil Armstrong 
>>> <narmstrong@baylibre.com>
>>> Cc: linux-amlogic at lists.infradead.org
>>> Subject: RE: Odroid-C2 solid green screen on "echo c > 
>>> /proc/sysrq-trigger" on Arch 4.16/4.17rc6
>>>
>>> I just had a look at the Arch linux PKGBUILD for the uboot package I am using, and it is mainline 2017.07. So I am using the mainline uboot, just a bit older.
>>>
>>> I?ll give Armbian a try ? is it the distro wit1h the most development so far? (Other than the 3.14.x releases which I would prefer not to use for now).
>>>
>>> Matthew
>>>
>>> Dr. Matthew Swabey - Director
>>> Bechtel Innovation Design Center - Purdue University
>>> room: BIDC 225? ? ? phone: +1-765-494-8655
>>>
>>> From: Tony McKahan [mailto:tonymckahan at gmail.com]
>>> Sent: Friday, May 25, 2018 3:46 PM
>>> To: Neil Armstrong <narmstrong@baylibre.com>
>>> Cc: Swabey, Matthew A <maswabey@purdue.edu>; 
>>> linux-amlogic at lists.infradead.org
>>> Subject: Re: Odroid-C2 solid green screen on "echo c > 
>>> /proc/sysrq-trigger" on Arch 4.16/4.17rc6
>>>
>>> Hello Neil, Matt,
>>>
>>> Change to 2018.03 is in Armbian's development branch, just waiting to be rolled into the master.? I don't have this particular board for testing, but it should be updated soon.
>>>
>>> On Fri, May 25, 2018, 3:57 AM Neil Armstrong <mailto:narmstrong@baylibre.com> wrote:
>>> Hi,
>>>
>>> On 25/05/2018 04:19, Swabey, Matthew A wrote:
>>>> Odroid-C2 solid green screen on echo c > /proc/sysrq-trigger on Arch 
>>>> Linux mainline 4.16/4.17rc6 Using lightdm on xorg fb. No mali, utgard or odroid specific framebuffers. However it seems to happen on them too.
>>>>
>>>> Steps to reproduce:
>>>> 1. Boot
>>>> 2. Echo c > /proc/sysrq-trigger with watchdog set. Or trigger the watchdog another way, i.e. watchdogd or system.
>>>> 3. Watchdog causes reboot
>>>> 4. Boots with screen solid green, see photo here: 
>>>> https://photos.app.goo.gl/9VyiweNAIMD07VSM2
>>>> ? ? ? ?a. No error messages visible, see attached log file bundles 
>>>> containing dmesg, journalctl, package list, Xorg.0.log
>>>> ? ? ? ?b. Linux-aarch64 is 4.16
>>>> ? ? ? ?c. Linux-aarch64-rc is 4.17rc6 5. Reboot - screen back to 
>>>> normal and working
>>> Well, since screen goes back to normal means there is no bug on the kernel side.
>>>
>>> This is caused by Amlogic's U-Boot.
>>> The HW watchdog does a complete SoC reset, we cannot execute any code from kernel when the watchdog wakes up.
>>>
>>> Please report this to Armbian and ask them to use Mainline U-Boot, this won't happen anymore.
>>>
>>> Neil
>>>
>>>>
>>>> Thought - something about the way to trigger this reset isn't working, or a race condition is present which is being more reliably triggered? Perhaps in the dma controller or the HDMI?
>>>>
>>>> Any help to track this bug down would be very helpful, or someone else who would be interested? I can't figure out where in the stack the problem is occurring, but I guess it is the bootloader.
>>>>
>>>> Thanks,
>>>>
>>>> Matthew
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> linux-amlogic mailing list
>>>> mailto:linux-amlogic at lists.infradead.org
>>>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
>>>>
>>>
>>>
>>> _______________________________________________
>>> linux-amlogic mailing list
>>> mailto:linux-amlogic at lists.infradead.org
>>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
>>> _______________________________________________
>>> linux-amlogic mailing list
>>> linux-amlogic at lists.infradead.org
>>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
>>>
>>
>>
>> _______________________________________________
>> linux-amlogic mailing list
>> linux-amlogic at lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
>>
> 

Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6

[Swabey, Matthew A]

Update: The solid green screen can occasionally happen on normal power cycling. I thought it had done it one time during development, but I wasn't sure. Now another test Odroid-c2 did it when the building power was lost and came back on, but its partner didn't. So it isn't just the watchdog reset that can cause this failure. Again, no error messages and the odroid thinks X is running as I can ssh in and see the CPU load of chromium rendering web video etc. as per normal boot.

Answer to your question, why watchdog (apologies for length, but context may help):
I direct the Bechtel Innovation Design Center at Purdue, it is a super student makerspace with a lot of high tech equipment. At the moment I have about 16-odd raspberry pi's deployed as both digital signs and some as machine interlocks. The next deployment will be about 40-50 single board computers. Some of the signs are pretty inaccessible, etc. The others run machine interlocks. All run network monitoring and occasionally one would need rebooting after hanging. After enabling the watchdog that wasn't a problem anymore.

I'm not happy with the Raspberry Pi 3B, never really have been happy with any of their products due to their weird bootloader (just google netbooting Rpis - their implementation is badly broken), their overall hardware architecture etc. I much prefer the Odroid-c2, except for the 3.14 kernel. So when it went mainline I was very happy.

However the reboot-greenscreen is problematic for my usecase, and I believe indicative of a possible race somewhere in the software stack, probably bootloader.

Serial port adapter arrives soon, I already have the JTAG equipment I need so with the echo c > /proc.. reproducible test case I hope to be able to 100% lock it down to exactly when it is triggered and then start diffing things to try to get to the bottom of it.

If you have any nasty suspicions of where the issue might lurk please share, I have seen "green overlay" talked about before with the meson, but this seems quite different.

Matthew

Dr. Matthew Swabey - Director?
Bechtel Innovation Design Center - Purdue University
room: BIDC 225? ? ? phone: +1-765-494-8655

-----Original Message-----
From: Neil Armstrong <narmstrong@baylibre.com> 
Sent: Tuesday, June 5, 2018 5:17 AM
To: Swabey, Matthew A <maswabey@purdue.edu>; Micha? Zegan <webczat_200@poczta.onet.pl>; Tony McKahan <tonymckahan@gmail.com>
Cc: linux-amlogic at lists.infradead.org
Subject: Re: Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6

Hi,

Having the watchdog to reset the board is an exceptional event, why would you bother fixing this ?

Neil

On 04/06/2018 23:22, Swabey, Matthew A wrote:
> Well, as an update.
> 
> Using arch linux for arm, modified their PKGBUILD to build u-boot 2018.05 with no patches at all. Signed and wrote to SD-CARD as per usual. 
> 
> Green screen on echo c > /proc/sysrq-trigger after watchdog reset.
> No green screen on shutdown -r
> 
> Temporary solution for me will be to play a "double reboot" game with a fingerprint file to see if it was shutdown cleanly or not.
> 
> Best,
> 
> Matthew
> 
> Dr. Matthew Swabey - Director
> Bechtel Innovation Design Center - Purdue University
> room: BIDC 225? ? ? phone: +1-765-494-8655
> 
> -----Original Message-----
> From: Micha? Zegan <webczat_200@poczta.onet.pl>
> Sent: Saturday, May 26, 2018 4:50 AM
> To: Neil Armstrong <narmstrong@baylibre.com>; Swabey, Matthew A 
> <maswabey@purdue.edu>; Tony McKahan <tonymckahan@gmail.com>
> Cc: linux-amlogic at lists.infradead.org
> Subject: Re: Odroid-C2 solid green screen on "echo c > 
> /proc/sysrq-trigger" on Arch 4.16/4.17rc6
> 
> What about the *kernel* resetting at boot?
> 
> W dniu 26.05.2018 o?10:33, Neil Armstrong pisze:
>> Hi,
>>
>> I'm sorry to disappoint you, but with the HW watchdog, we *can't* execute any code from Linux when the watchdoog resets the system.
>> We could eventually add some code in U-Boot to disable the HDMI output, but U-boot is not the first code executed, you will still see the green screen.
>> You may need to contact Hardkernel to see if they can update the BL* binaries to include such reset.
>>
>> Neil
>>
>> On 26/05/2018 05:49, Swabey, Matthew A wrote:
>>> Can also confirm green screen on watchdog reboot from "echo c > /proc/sysrq-trigger" for Armbian 5.44 with linux-u-boot-odroidc2-next version 2018.03.
>>>
>>> This is in addition to the Armbian bug where shutdown -r now doesn?t reboot the system, just either freezes or powers down. Supposed to be fixed on 2018.03 but not working for me.
>>>
>>> Matthew
>>>
>>> Dr. Matthew Swabey - Director
>>> Bechtel Innovation Design Center - Purdue University
>>> room: BIDC 225? ? ? phone: +1-765-494-8655
>>>
>>> -----Original Message-----
>>> From: linux-amlogic
>>> [mailto:linux-amlogic-bounces at lists.infradead.org] On Behalf Of 
>>> Swabey, Matthew A
>>> Sent: Friday, May 25, 2018 10:37 PM
>>> To: Tony McKahan <tonymckahan@gmail.com>; Neil Armstrong 
>>> <narmstrong@baylibre.com>
>>> Cc: linux-amlogic at lists.infradead.org
>>> Subject: RE: Odroid-C2 solid green screen on "echo c > 
>>> /proc/sysrq-trigger" on Arch 4.16/4.17rc6
>>>
>>> I just had a look at the Arch linux PKGBUILD for the uboot package I am using, and it is mainline 2017.07. So I am using the mainline uboot, just a bit older.
>>>
>>> I?ll give Armbian a try ? is it the distro wit1h the most development so far? (Other than the 3.14.x releases which I would prefer not to use for now).
>>>
>>> Matthew
>>>
>>> Dr. Matthew Swabey - Director
>>> Bechtel Innovation Design Center - Purdue University
>>> room: BIDC 225? ? ? phone: +1-765-494-8655
>>>
>>> From: Tony McKahan [mailto:tonymckahan at gmail.com]
>>> Sent: Friday, May 25, 2018 3:46 PM
>>> To: Neil Armstrong <narmstrong@baylibre.com>
>>> Cc: Swabey, Matthew A <maswabey@purdue.edu>; 
>>> linux-amlogic at lists.infradead.org
>>> Subject: Re: Odroid-C2 solid green screen on "echo c > 
>>> /proc/sysrq-trigger" on Arch 4.16/4.17rc6
>>>
>>> Hello Neil, Matt,
>>>
>>> Change to 2018.03 is in Armbian's development branch, just waiting to be rolled into the master.? I don't have this particular board for testing, but it should be updated soon.
>>>
>>> On Fri, May 25, 2018, 3:57 AM Neil Armstrong <mailto:narmstrong@baylibre.com> wrote:
>>> Hi,
>>>
>>> On 25/05/2018 04:19, Swabey, Matthew A wrote:
>>>> Odroid-C2 solid green screen on echo c > /proc/sysrq-trigger on 
>>>> Arch Linux mainline 4.16/4.17rc6 Using lightdm on xorg fb. No mali, utgard or odroid specific framebuffers. However it seems to happen on them too.
>>>>
>>>> Steps to reproduce:
>>>> 1. Boot
>>>> 2. Echo c > /proc/sysrq-trigger with watchdog set. Or trigger the watchdog another way, i.e. watchdogd or system.
>>>> 3. Watchdog causes reboot
>>>> 4. Boots with screen solid green, see photo here: 
>>>> https://photos.app.goo.gl/9VyiweNAIMD07VSM2
>>>> ? ? ? ?a. No error messages visible, see attached log file bundles 
>>>> containing dmesg, journalctl, package list, Xorg.0.log
>>>> ? ? ? ?b. Linux-aarch64 is 4.16
>>>> ? ? ? ?c. Linux-aarch64-rc is 4.17rc6 5. Reboot - screen back to 
>>>> normal and working
>>> Well, since screen goes back to normal means there is no bug on the kernel side.
>>>
>>> This is caused by Amlogic's U-Boot.
>>> The HW watchdog does a complete SoC reset, we cannot execute any code from kernel when the watchdog wakes up.
>>>
>>> Please report this to Armbian and ask them to use Mainline U-Boot, this won't happen anymore.
>>>
>>> Neil
>>>
>>>>
>>>> Thought - something about the way to trigger this reset isn't working, or a race condition is present which is being more reliably triggered? Perhaps in the dma controller or the HDMI?
>>>>
>>>> Any help to track this bug down would be very helpful, or someone else who would be interested? I can't figure out where in the stack the problem is occurring, but I guess it is the bootloader.
>>>>
>>>> Thanks,
>>>>
>>>> Matthew
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> linux-amlogic mailing list
>>>> mailto:linux-amlogic at lists.infradead.org
>>>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
>>>>
>>>
>>>
>>> _______________________________________________
>>> linux-amlogic mailing list
>>> mailto:linux-amlogic at lists.infradead.org
>>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
>>> _______________________________________________
>>> linux-amlogic mailing list
>>> linux-amlogic at lists.infradead.org
>>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
>>>
>>
>>
>> _______________________________________________
>> linux-amlogic mailing list
>> linux-amlogic at lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-amlogic
>>
> 

Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6

[Jerome Brunet]

On Tue, 2018-06-05 at 13:48 +0000, Swabey, Matthew A wrote:
> I'm not happy with the Raspberry Pi 3B, never really have been happy with any of their products due to their weird bootloader (just google netbooting Rpis - their implementation is badly broken), their overall hardware architecture etc. I much prefer the Odroid-c2, except for the 3.14 kernel. So when it went mainline I was very happy.
> 
> However the reboot-greenscreen is problematic for my usecase, and I believe indicative of a possible race somewhere in the software stack, probably bootloader.

I don't think so.
My guess would be that your screen somehow read raw '0x00' on link while the
board resets. If your display is configured in YUV mode, you would see a green
screen. 0,0,0 is green in YUV

If you were using RGB instead YUV, I suspect you would have a black screen,
which is sad compared to 'funky green' but it is matter of taste I suppose.

Odroid-C2 solid green screen on "echo c > /proc/sysrq-trigger" on Arch 4.16/4.17rc6

[Neil Armstrong]

On 05/06/2018 18:07, Jerome Brunet wrote:
> On Tue, 2018-06-05 at 13:48 +0000, Swabey, Matthew A wrote:
>> I'm not happy with the Raspberry Pi 3B, never really have been happy with any of their products due to their weird bootloader (just google netbooting Rpis - their implementation is badly broken), their overall hardware architecture etc. I much prefer the Odroid-c2, except for the 3.14 kernel. So when it went mainline I was very happy.
>>
>> However the reboot-greenscreen is problematic for my usecase, and I believe indicative of a possible race somewhere in the software stack, probably bootloader.
> 
> I don't think so.
> My guess would be that your screen somehow read raw '0x00' on link while the
> board resets. If your display is configured in YUV mode, you would see a green
> screen. 0,0,0 is green in YUV
> 
> If you were using RGB instead YUV, I suspect you would have a black screen,
> which is sad compared to 'funky green' but it is matter of taste I suppose.
> 

As I explained in a previous answer, the Watchog reset stops the whole SoC at a single point and reboots.
There is no way to handle this in software since it's designed to reset the SoC when the software is stuck.

As Jerome explained, the HDMI PHY is probably still sending some TMDS data but half of the SoC must in reset state,
thus sending data from YUV '0's. The HDMI on GXBB is configured to always send RGB, but the video converter must
still work when the reset occurs, thus seeing the last zero frame on the screen.

In watchdog reset, the fix is quite limited. As I replied earlier, it may be necessary to reset the HDMI
PHY in early code, but this code is in the control of Amlogic, and maybe HardKernel.
Anyway this SoC is no longer supported by Amlogic, so anything related to Firmware won't be fixed.
It should be interesting to see if the issue remains on the S905X/S905D SoCs.

Finally, if you see the same green screen after a normal shutdown/reboot command, this is another issue
and it means the HDMI disabling misses some code to avoid sending bad TMDS to the monitor.
This could be fixed for sure.

Neil