Re: MGA G200 issue in 6.12 and up
From: Thomas Zimmermann
Date: Wed Apr 16 2025 - 04:47:56 EST
Hi,
thanks for reporting.
Am 16.04.25 um 03:46 schrieb David Airlie:
adding some people
On Tue, Apr 15, 2025 at 10:35 AM Wakko Warner <wakko@xxxxxxxxxxxx> wrote:
I found the fix that works for me. See below.
Wakko Warner wrote:
I decided to upgrade to 6.14 on a system with a Matrox G200 onboard vga
(supermicro X9SCL).
I use this system via the BMC. When the mgag200 driver loads, the bmc
screen flashes between no signal and the screen. The rate seems to be about
1 second no signal and 1 second with signal.
6.12 and 6.13 both have this problem.
6.11 does not have this problem.
I have a monitor plugged into the vga port and it doesn't have this problem
on any of the kernels I've tried. Only the remote connection through the bmc
has this problem. I have booted the system with and with out the monitor
plugged in, it does not appear to make a difference.
I found a thread on arch linux forums
(https://bbs.archlinux.org/viewtopic.php?id=303819) where the op has the
same issue. He bisected and came up with the bad commit.
That commit is
d6460bd52c27fde97d6a73e3d9c7a8d747fbaa3e drm/mgag200: Add dedicated variables
for blanking fields
I searched this commit and manually reverted it from my vanilla 6.14 and it
works fine. No blinking in the BMC remote console and the external VGA
works fine as well.
I sent out a patch for what I think is the problem. See
https://lore.kernel.org/dri-devel/20250416083847.51764-1-tzimmermann@xxxxxxx/
Testing and feedback would be much appreciated.
Best regards
Thomas
--
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Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
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