Modesetting (amdgpudrmfb) artifacts on RAVEN APU

[Harry Wentland]

Yup, that's there as

commit e92b44fdee3ec0b679bacdb9c7e95e55699167f0
Author: Tony Cheng <tony.cheng at amd.com>
Date:   Thu Oct 5 14:38:46 2017 -0400

    drm/amd/display: default force_single_disp_pipe_split = 1 on RV

...


Harry

On 2018-03-07 02:16 PM, Tom St Denis wrote:
> It's an old patch but does drm-fixes-4.16 have this patch
> 
> commit e92b44fdee3ec0b679bacdb9c7e95e55699167f0
> Refs: v4.14-rc3-1871-ge92b44fdee3e
> Author:     Tony Cheng <tony.cheng at amd.com>
> AuthorDate: Thu Oct 5 14:38:46 2017 -0400
> Commit:     Alex Deucher <alexander.deucher at amd.com>
> CommitDate: Sat Oct 21 16:52:21 2017 -0400
> 
>     drm/amd/display: default force_single_disp_pipe_split = 1 on RV
> 
>     1080p idle, stutter efficiency goes up from 95.8% to 97.8%
>     result in 5mW saving from APU and 8mW saving from DDR4
> 
>     Signed-off-by: Tony Cheng <tony.cheng at amd.com>
>     Reviewed-by: Yongqiang Sun <yongqiang.sun at amd.com>
>     Acked-by: Harry Wentland <Harry.Wentland at amd.com>
>     Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
> 
> ?
> 
> Tom
> 
> On 03/07/2018 02:12 PM, Harry Wentland wrote:
>> On 2018-03-07 12:38 PM, KARBOWSKI Piotr wrote:
>>> On 2018-03-07 17:48, KARBOWSKI Piotr wrote:
>>>> On 2018-03-07 17:14, Harry Wentland wrote:
>>>>> Pushed a drm-fixes-4.16 branch (based on Alex's) to my FDO repo athttps://cgit.freedesktop.org/~hwentland/linux/  but I don't have a Raven system setup to test this at the moment.
>>>>>
>>>>> Tom, or Piotr, would you be able to check that the fix works as intended on that branch?
>>>>
>>>> Tested that branch, confirmed that the VGA patch is there but I got the original result of broken video. Rebooted few times. It seems that my issue was not the VGA turnover afterall. I will re-test it with vanilla amd-staging-drm-next of git://people.freedesktop.org/~agd5f/linux without the VGA patch and update you.
>>
>> Thanks for testing.
>>
>> What do you mean with broken video? I tried going back in the email thread but I'm not 100% clear what you mean by this.
>>
>> BTW, drm-fixes-4.16 are fixes we intend to get into the 4.16 upstream kernel. amd-staging-drm-next is our development tree and quite a bit farther ahead in development. I'm trying to find fixes to backmerge to 4.16 to make everyone happy when it releases.
>>
>> Harry
>>
>>>
>>> I re-tested original tree of git://people.freedesktop.org/~agd5f/linux on branch amd-staging-drm-next and got the 'double screen' glitches, then I applied the patch Tom sent me as the very first response to this thread and then it indeed fixed it. So the VGA takeover patch is needed it, it seems.
>>>
>>> I triple checked and build the images and the drm-fixes-4.16 of git://people.freedesktop.org/~hwentland/linux does not fix the problem for me.
>>>
>>> So far only amd-staging-drm-next with 0001-drm-amd-display-Fix-takeover-from-VGA-mode.patch does the trick. One thing worth note is that the amd-staging-drm-next goes as `rc1` where yours fork Harry appears to be rc3, no idea if it's related or not.
>>>
>>> -- Piotr.