commit 15512021eb3975a8c2366e3883337e252bb0eee5 causes white spots in console screens

[François Valenduc]

Le 14/04/22 à 08:31, Lisovskiy, Stanislav a écrit :
> On Wed, Apr 13, 2022 at 08:12:20PM +0300, Jani Nikula wrote:
>> On Wed, 13 Apr 2022, François Valenduc <francoisvalenduc at gmail.com> wrote:
>>> Commit 15512021eb3975a8c2366e3883337e252bb0eee5
>>> (15512021eb3975a8c2366e3883337e252bb0eee5) causes a lof of white spots
>>> to appears on the right upper corner of all console screens (see
>>> https://drive.google.com/file/d/13GabEvOIKSAj5yox6ybAZEDu3Ixncw5Q/view).
>>> git-bisect shows that this is the offending commit and if I revert it,
>>> the problem goes away. The problem still occurs with kernel 5.18-rc2 and
>>> to all stable trees where it was applied.
>>> Can somebody explains what happens ?
>>>
>>> The video card is the following: VGA compatible controller: Intel
>>> Corporation WhiskeyLake-U GT2 [UHD Graphics 620] (rev 02) (prog-if 00
>>> [VGA controller])
>>>
>>> Please tell me if you need more info.
>> That's commit 15512021eb39 ("drm/i915: Workaround broken BIOS DBUF
>> configuration on TGL/RKL"), adding Cc's.
>>
>> Please file a report at fdo gitlab [1] and attach dmesg etc. there.
> That commit looks like it is just disabling all the planes, if wrong
> dbuf/wm configuration is detected.
> However it should do that only once during boot as I understand.
>
> Are you sure that is exactly this commit which is causing this?
> Does the issue appear always?
>
> Ville Syrjälä, thoughts?
>
> Stan
>
>> Thanks,
>> Jani.
>>
>>
>> [1] https://gitlab.freedesktop.org/drm/intel/wikis/How-to-file-i915-bugs
>>
>>
>> -- 
>> Jani Nikula, Intel Open Source Graphics Center

As I said, git-bisect shows it's the offending commit and if I revert 
it, the problem doesn't happens. Otherwise, it always occurs.

François