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
The bad commit is
commit 6f719373b943a955fee6fc2012aed207b65e2854 Author: Thomas Zimmermann tzimmermann@suse.de Date: Tue Oct 14 10:46:34 2025 +0200
drm/ast: Blank with VGACR17 sync enable, always clear VGACRB6 sync off
Blank the display by disabling sync pulses with VGACR17<7>. Unblank by reenabling them. This VGA setting should be supported by all Aspeed hardware.
When I revert this from 6.18-rc2, the issue goes away and my console screen works again.
I just saw that Greg just yesterday evening included the offending patch already in stable RCs 6.12.55-rc1 and 6.17.5-rc1, so I'll test these seperately and send a mail to the stable mailing list, too, if affected (which I anticipate).
Beste Grüße, Peter Schneider