blank screen on boot with i915/DRM_FBDEV_EMULATION

blank screen on boot with i915/DRM_FBDEV_EMULATION

[Florian Zumbiehl]

Hi,

I just compiled a new kernel version 4.4.5, replacing a previous 4.1.9 for
my thinkpad x40, which replaced CONFIG_DRM_I915_FBDEV with
CONFIG_DRM_FBDEV_EMULATION--now, when the i915 and fbcon modules get loaded
during boot, the screen goes blank (with backlight still on), which didn't
happen with the old kernel.

The funny thing is that starting an X server makes text reappear on the
console!? (And the X server also works just fine, as far as I can tell so
far ...)

i915 is loaded with modeset=1 (I remember I had some problem without it
with some earlier kernels, I don't really remember the details anymore
...).

Any hints what to try? Any further information that could be useful?

Regards, Florian

Re: blank screen on boot with i915/DRM_FBDEV_EMULATION

[Daniel Vetter]

On Sat, Mar 26, 2016 at 12:21:23PM +0100, Florian Zumbiehl wrote:
> Hi,
> 
> I just compiled a new kernel version 4.4.5, replacing a previous 4.1.9 for
> my thinkpad x40, which replaced CONFIG_DRM_I915_FBDEV with
> CONFIG_DRM_FBDEV_EMULATION--now, when the i915 and fbcon modules get loaded
> during boot, the screen goes blank (with backlight still on), which didn't
> happen with the old kernel.
> 
> The funny thing is that starting an X server makes text reappear on the
> console!? (And the X server also works just fine, as far as I can tell so
> far ...)
> 
> i915 is loaded with modeset=1 (I remember I had some problem without it
> with some earlier kernels, I don't really remember the details anymore
> ...).
> 
> Any hints what to try? Any further information that could be useful?

FBDEV_EMULATION vs. I915_FBDEV is probably a read herring, more likely is
that for some odd reason the very first modeset fails. Once X has
resurrect the screen, can you then switch to fbcon? Also please check in
/sys/class/vtconsole whether the fbdev driver is loaded and bound (check
the name and bind files). And make sure there's that dmesg still says it
initialized the "inteldrmfb" driver.

If that all indicates fbcon is running properly, then it's time to bisect
what exactly broke the initial modeset for your system.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Re: blank screen on boot with i915/DRM_FBDEV_EMULATION

[Florian Zumbiehl]

Hi,

> FBDEV_EMULATION vs. I915_FBDEV is probably a read herring, more likely is
> that for some odd reason the very first modeset fails. Once X has
> resurrect the screen, can you then switch to fbcon? Also please check in
> /sys/class/vtconsole whether the fbdev driver is loaded and bound (check
> the name and bind files). And make sure there's that dmesg still says it
> initialized the "inteldrmfb" driver.

Trying to collect that information actually solved the problem: fbcon
didn't actually get loaded during boot, only the graphics drivers, which
caused the screen to go blank, loading fbcon happened only when starting
the X server ... seems weird to me, but I guess there is some non-obvious
logic behind that, and in any case it seems to be a change in behaviour.
Well, thanks for the pointer anyway, I guess! ;-)

Now, while at it: I also have a bunch of WARN_ONs and ERRORs happening (the
former primarily when an Xv window disappears from the screen, it seems,
the latter primarily during boot), which don't seem to have any immediate
negative effects at the surface, like this:

| [   14.815467] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
| [   14.815642] [drm:intel_set_cpu_fifo_underrun_reporting [i915]] *ERROR* pipe B underrun
| [   14.815806] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun
| [   14.823686] [drm] initialized overlay support
| [   14.873165] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun

| [ 2520.457732] WARNING: CPU: 0 PID: 3193 at drivers/gpu/drm/i915/i915_gem.c:4508 i915_gem_free_object+0x277/0x280 [i915]()
| [ 2520.457736] WARN_ON(obj->frontbuffer_bits)

Also, I have occasional X server crashes (every few weeks or so) which
started with 4.1.9, I think (I had 3.11.0 before that), and I had some kind
of problem with Xv not working anymore until reboot with 4.1.9 which hasn't
happened with 4.4.5 yet ... do you think any of those would be worth
further investigation? If so, any suggestions as to how to split it all
into separate issues/how to go about it?

Regards, Florian

Re: [Intel-gfx] blank screen on boot with i915/DRM_FBDEV_EMULATION

[Daniel Vetter]

On Tue, Mar 29, 2016 at 06:44:57PM +0200, Florian Zumbiehl wrote:
> Hi,
> 
> > FBDEV_EMULATION vs. I915_FBDEV is probably a read herring, more likely is
> > that for some odd reason the very first modeset fails. Once X has
> > resurrect the screen, can you then switch to fbcon? Also please check in
> > /sys/class/vtconsole whether the fbdev driver is loaded and bound (check
> > the name and bind files). And make sure there's that dmesg still says it
> > initialized the "inteldrmfb" driver.
> 
> Trying to collect that information actually solved the problem: fbcon
> didn't actually get loaded during boot, only the graphics drivers, which
> caused the screen to go blank, loading fbcon happened only when starting
> the X server ... seems weird to me, but I guess there is some non-obvious
> logic behind that, and in any case it seems to be a change in behaviour.
> Well, thanks for the pointer anyway, I guess! ;-)
> 
> Now, while at it: I also have a bunch of WARN_ONs and ERRORs happening (the
> former primarily when an Xv window disappears from the screen, it seems,
> the latter primarily during boot), which don't seem to have any immediate
> negative effects at the surface, like this:
> 
> | [   14.815467] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
> | [   14.815642] [drm:intel_set_cpu_fifo_underrun_reporting [i915]] *ERROR* pipe B underrun
> | [   14.815806] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun
> | [   14.823686] [drm] initialized overlay support
> | [   14.873165] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun

We've fixed piles of those in recent kernels, but didn't backport all the
fixes (since usually it's a silent failure, but it can correlate with
black screens).
 
> | [ 2520.457732] WARNING: CPU: 0 PID: 3193 at drivers/gpu/drm/i915/i915_gem.c:4508 i915_gem_free_object+0x277/0x280 [i915]()
> | [ 2520.457736] WARN_ON(obj->frontbuffer_bits)

Hm, this one should be fixed, and the patches should all be correctly
marked for stable. Either there's a backlog somewhere, or we failed.

Would be great if you can test a drm-intel-nightly build (or 4.6-rc1) for
either and confirm that they're gone. And for the later we really should
hunt down the bugfix if it's stuck.

> Also, I have occasional X server crashes (every few weeks or so) which
> started with 4.1.9, I think (I had 3.11.0 before that), and I had some kind
> of problem with Xv not working anymore until reboot with 4.1.9 which hasn't
> happened with 4.4.5 yet ... do you think any of those would be worth
> further investigation? If so, any suggestions as to how to split it all
> into separate issues/how to go about it?

No idea about X stuff, not my expertise ;-)
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

i951 ERRORs and WARN_ON()s (was: blank screen on boot with i915/DRM_FBDEV_EMULATION)

[Florian Zumbiehl]

Hi,

> We've fixed piles of those in recent kernels, but didn't backport all the
> fixes (since usually it's a silent failure, but it can correlate with
> black screens).

Not quite completely, it seems ...

I have built drm-intel-nightly (f261f82359), and I'm getting this:

| [   15.855007] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
| [   15.855007] [drm:intel_set_cpu_fifo_underrun_reporting [i915]] *ERROR* pipe B underrun
| [   15.855007] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe B FIFO underrun
| [   15.863175] [drm] RC6 disabled, disabling runtime PM support
| [   15.863543] [drm] initialized overlay support
| [   15.933338] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun
| [   15.997130] i915 0000:00:02.0: fb0: inteldrmfb frame buffer device
| [   16.061856] [drm:intel_set_cpu_fifo_underrun_reporting [i915]] *ERROR* pipe A underrun
| [   16.725274] [drm] Initialized i915 1.6.0 20160330 for 0000:00:02.0 on minor 0
| [   16.805727] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe A FIFO underrun

> > | [ 2520.457732] WARNING: CPU: 0 PID: 3193 at drivers/gpu/drm/i915/i915_gem.c:4508 i915_gem_free_object+0x277/0x280 [i915]()
> > | [ 2520.457736] WARN_ON(obj->frontbuffer_bits)
> 
> Hm, this one should be fixed, and the patches should all be correctly
> marked for stable. Either there's a backlog somewhere, or we failed.
> 
> Would be great if you can test a drm-intel-nightly build (or 4.6-rc1) for
> either and confirm that they're gone. And for the later we really should
> hunt down the bugfix if it's stuck.

| [  141.999803] ------------[ cut here ]------------
| [  141.999916] WARNING: CPU: 0 PID: 3349 at drivers/gpu/drm/i915/i915_gem.c:4568 i915_gem_free_object+0x25f/0x270 [i915]
| [  141.999923] WARN_ON(obj->frontbuffer_bits)
| [  141.999928] Modules linked in: ipt_MASQUERADE nf_nat_masquerade_ipv4 xt_CT iptable_raw xt_nat xt_tcpudp xt_addrtype iptable_nat nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack ip_tables x_tables dummy tun nfsd exportfs nfs lockd grace sunrpc ipv6 fbcon bitblit softcursor font loop mousedev i915 i2c_algo_bit drm_kms_helper cfbfillrect syscopyarea cfbimgblt sysfillrect sysimgblt fb_sys_fops cfbcopyarea snd_intel8x0 drm snd_ac97_codec ac97_bus i2c_core snd_pcm_oss fb snd_mixer_oss fbdev snd_pcm ipw2200 snd_timer snd libipw soundcore lib80211 nsc_ircc thinkpad_acpi cfg80211 pcmcia psmouse sdhci_pci irda uhci_hcd ehci_pci sdhci crc_ccitt ehci_hcd serio_raw e1000 mmc_core nvram evdev usbcore parport_pc yenta_socket hwmon parport pcmcia_rsrc video usb_common pcmcia_core backlight ac battery acpi_cpufreq intel_agp processor button intel_gtt agpgart twofish_generic twofish_i586 twofish_common xts gf128mul dm_crypt dm_mod thermal
| [  142.000114] CPU: 0 PID: 3349 Comm: Xorg Not tainted 4.6.0-rc1+ #1
| [  142.000120] Hardware name: IBM 23716JG/23716JG, BIOS 1UETD3WW (2.08 ) 12/21/2006
| [  142.000127]  c11b8f7a c1037247 f8dea59b c0051dc4 00000d15 f8dda000 000011d8 f8d3ff2f
| [  142.000141]  f8d3ff2f 000011d8 f3ef1dcc f3ef1e30 f3ef1dcc f3ef1dc0 c1037309 00000009
| [  142.000154]  00000000 c0051dac f8dea59b c0051dc4 f8d3ff2f f8dda000 000011d8 f8dea59b
| [  142.000168] Call Trace:
| [  142.000185]  [<c11b8f7a>] ? dump_stack+0xa/0x20
| [  142.000197]  [<c1037247>] ? __warn+0xe7/0x100
| [  142.000269]  [<f8d3ff2f>] ? i915_gem_free_object+0x25f/0x270 [i915]
| [  142.000337]  [<f8d3ff2f>] ? i915_gem_free_object+0x25f/0x270 [i915]
| [  142.000347]  [<c1037309>] ? warn_slowpath_fmt+0x39/0x40
| [  142.000416]  [<f8d3ff2f>] ? i915_gem_free_object+0x25f/0x270 [i915]
| [  142.000452]  [<f892ed83>] ? drm_gem_object_free+0x23/0x40 [drm]
| [  142.000478]  [<f892f58f>] ? drm_gem_object_handle_unreference_unlocked+0xcf/0xe0 [drm]
| [  142.000504]  [<f892f5e7>] ? drm_gem_object_release_handle+0x47/0x90 [drm]
| [  142.000529]  [<f892f67e>] ? drm_gem_handle_delete+0x4e/0x80 [drm]
| [  142.000554]  [<f892f8d0>] ? drm_gem_handle_create+0x30/0x30 [drm]
| [  142.000580]  [<f89302c0>] ? drm_ioctl+0x230/0x570 [drm]
| [  142.000606]  [<f892f8d0>] ? drm_gem_handle_create+0x30/0x30 [drm]
| [  142.000618]  [<c10b34a3>] ? unmap_page_range+0x433/0x530
| [  142.000627]  [<c11be1c3>] ? __rb_erase_color+0xf3/0x250
| [  142.000637]  [<c10b7116>] ? unlink_file_vma+0x36/0x70
| [  142.000645]  [<c10b1db9>] ? tlb_finish_mmu+0x9/0x30
| [  142.000671]  [<f8930090>] ? drm_ioctl_permit+0x80/0x80 [drm]
| [  142.000682]  [<c10e7250>] ? do_vfs_ioctl+0x80/0x6a0
| [  142.000690]  [<c11bf570>] ? timerqueue_del+0x20/0x70
| [  142.000699]  [<c10cbde5>] ? kmem_cache_free+0x95/0xa0
| [  142.000708]  [<c10b6d0e>] ? remove_vma+0x3e/0x50
| [  142.000717]  [<c10b9019>] ? do_munmap+0x219/0x2d0
| [  142.000726]  [<c10e78b3>] ? SyS_ioctl+0x43/0x80
| [  142.000735]  [<c1001272>] ? do_fast_syscall_32+0x82/0x110
| [  142.000745]  [<c134644f>] ? sysenter_past_esp+0x40/0x6a
| [  142.000777] ---[ end trace c0ddddf77cdb5434 ]---

Each time an Xv window disappears from view--sometimes with slight
variations in the stacktrace. Do you need full debug info or a bunch more
stacktraces or is this enough to get an idea?

> > Also, I have occasional X server crashes (every few weeks or so) which
> > started with 4.1.9, I think (I had 3.11.0 before that), and I had some kind
> > of problem with Xv not working anymore until reboot with 4.1.9 which hasn't
> > happened with 4.4.5 yet ... do you think any of those would be worth
> > further investigation? If so, any suggestions as to how to split it all
> > into separate issues/how to go about it?
> 
> No idea about X stuff, not my expertise ;-)

Well, I would guess that something that persists until reboot smells like a
kernel/driver bug? Also, IIRC, there was no (major) X server upgrade
between 3.11.0 and 4.1.9, so chances are that's a kernel/driver bug as well
;-)

Regards, Florian

Re: i951 ERRORs and WARN_ON()s (was: blank screen on boot with i915/DRM_FBDEV_EMULATION)

[Florian Zumbiehl]

Hi,

> > We've fixed piles of those in recent kernels, but didn't backport all the
> > fixes (since usually it's a silent failure, but it can correlate with
> > black screens).
> 
> Not quite completely, it seems ...
> 
> I have built drm-intel-nightly (f261f82359), and I'm getting this:
[...]

ping?

Regards, Florian

Re: [Intel-gfx] i951 ERRORs and WARN_ON()s (was: blank screen on boot with i915/DRM_FBDEV_EMULATION)

[Marius Vlad]

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Florian, if you're using drm-intel-nigthly submit a bug at
https://bugs.freedesktop.org/enter_bug.cgi?product=DRI, with DRM/intel
as component. This way we can track some kind of progress/regress. The FIFO
underruns should've have been fixed, but maybe there's something related
to your platform.

On Tue, Apr 12, 2016 at 03:23:08AM +0200, Florian Zumbiehl wrote:
> Hi,
> 
> > > We've fixed piles of those in recent kernels, but didn't backport all the
> > > fixes (since usually it's a silent failure, but it can correlate with
> > > black screens).
> > 
> > Not quite completely, it seems ...
> > 
> > I have built drm-intel-nightly (f261f82359), and I'm getting this:
> [...]
> 
> ping?
> 
> Regards, Florian
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

[-- Attachment #2: Digital signature --]
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Re: [Intel-gfx] i951 ERRORs and WARN_ON()s (was: blank screen on boot with i915/DRM_FBDEV_EMULATION)

[Florian Zumbiehl]

Hi,

> Florian, if you're using drm-intel-nigthly submit a bug at
> https://bugs.freedesktop.org/enter_bug.cgi?product=DRI, with DRM/intel
> as component. This way we can track some kind of progress/regress. The FIFO

Gee ... is there any way without "creating an account"? Having to create
accounts everywhere to be able to communicate with people just sucks. I
mean, do you want to create an account in my todo tracker and use my todo
tracker's web interface to coordinate the bug investigation? Use whatever
software you like for managing your todo lists, but please, don't bother me
with having to use it for you.

> underruns should've have been fixed, but maybe there's something related
> to your platform.

You mean the ones I reported a month ago should be fixed? Should I try a
newer nightly to check?

What about the Xv stuttering?

Regards, Florian