Re: [REGRESSION][BISECTED] Screen goes blank with ASpeed AST2300 in 6.18-rc2

[Peter Schneider <pschneider1968@googlemail.com>]

Hi Thomas,

thanks very much for your quick response!

(adding Thorsten to CC)


Am 22.10.2025 um 08:51 schrieb Thomas Zimmermann:
> Hi
> 
> Am 22.10.25 um 05:27 schrieb Peter Schneider:
>> #regzbot introduced: 6f719373b943a955fee6fc2012aed207b65e2854
>>
>> Hi all,
>>
>> I have encountered a serious (for me) regression with 6.18-rc2 on my 2-socket Ivy Bridge Xeon E5-2697 v2 server. After 
>> booting, my console screen goes blank and stays blank. 6.18-rc1 was still fine.
>>
>> The machine has an Asus Z9PE-D16 server mainboard with an onboard ASpeed AST2300 VGA chip with 16MB VRAM. I have 
>> attached an older HP Monitor to it via old VGA jack/cable. It also has a second graphics card in a PCI-E slot; an 
>> older NVidia GTX 560. It is not connected to a monitor, but I have configured it via kernel command line for PCI-pass- 
>> through to VMs running on this server (I use Proxmox VE, i.e. QEMU/KVM virtual machines). Currently, no VMs use this 
>> yet, and also no VMs are autostarting with machine boot. So when this regression occurs, the server is idle. Pressing 
>> a key on the keyboard does not make the screen come alive. The server is running fine though, and I can access it via 
>> SSH. It just has no graphic output anymore. In case this is important, the machine also has a ASMB6 BMC (can be used 
>> via http).
>>
>> I have attached dmesg output from both 6.18-rc1 which is fine, and 6.18-rc2 which exhibits this bug. I have bisected 
>> the issue, please see attached git bisect.log.
> 
> Thanks for the detailed bug report.
> 
> Attached is a patch that partially reverts the broken commit. Could you please apply it on top of the broken kernel and 
> report on the results?
> 
> Best regards
> Thomas


Your patch applied cleanly against 6.18-rc2 and the kernel built fine, but unfortunately it did not solve the issue: my 
console screen stays blank after booting. This is regardless whether I do a soft reboot, press the reset button or power 
cycle and do a cold boot. They are all the same.


Beste Grüße,
Peter Schneider

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