[Intel-gfx] [bug report] drm/i915: Computer does not shutdown,

[Hans de Goede]

Hi,

On 3/22/21 3:53 PM, Ville Syrjälä wrote:
> On Mon, Mar 22, 2021 at 11:45:39AM +0100, Hans de Goede wrote:
>> Hi,
>>
>> On 3/14/21 11:30 AM, Mario Hüttel wrote:
>>> Hello,
>>>
>>> It seems, like the mailing list, didn't accept my email. So I'll send
>>> it again:
>>>
>>> I want to report a bug. I have a PC with Intel i7-6700K processor (with
>>> integrated graphics) and an AsRock Fatal1ty Z170 Gaming K6 mainboard. I
>>> use the CPU's integrated graphics.
>>> My system is Archlinux with Kernel v5.11.6.
>>>
>>> Using this setup, my PC works normally. However, when I shut it down,
>>> the power is not cut. Fans keep spinning and LEDs stay on. I couldn't
>>> detect any other problem when shutting down. Drives etc. stop as
>>> expected and the video is blank. Even after waiting several hours, the
>>> system doesn't power down.
>>>
>>> Restarts work normally.
>>>
>>> I haven't yet found any other people on the internet that have the same
>>> bug.
>>>
>>> I used git bisect to find the commit that causes this behavior on my
>>> machine.
>>
>> Thank you for doing a bisect that is always very helpful.
>>
>>> The result is: fe0f1e3bfdfeb53e18f1206aea4f40b9bd1f291c is the
>>> first bad commit.
>>
>> To save others the trouble of having to look up the hasj, that is:
>>
>> "drm/i915: Shut down displays gracefully on reboot"
>>
>> Which is the same commit as which I've reported is causing issues
>> with DSI panels not lighting up on reboots on some BYT/CHT devices.
>>
>> Since this seems to mostly be intended to fix issues surrounding
>> DP MST stuff, maybe the graceful shutdown should only be done when
>> MST is in use?
> 
> No. It also fixes Windows, lols.

Ok, can you at least take a look at my patch which fixes (works-around)
the issues for DSI panel on BYT/CHT DSI devices:

https://patchwork.freedesktop.org/patch/422481/

?

In that case the display stays black after reboot in the BIOS / in apps
using the EFI fb/console such as the grub menu and when using fastboot
it also stays black under Linux (I did not test Windows) only after forcing
a modeset under Linux the DSI LCD panel works again.

As I mention in the commit msg given the age of the platforms involved
I think that a simple workaround as I suggest there is best.

Regards,

Hans