[PATCH] Revert "drm/amd/display: Program OTG vtotal min/max selectors unconditionally for DCN1+"

[Pillai, Aurabindo]

[Public]

Hi Guilherme,

Sorry there was one more patch which I missed to attach. Please add this 3rd patch and retry.

Reverting that patch would cause high power consumption on Navi2x GPU also cause hangs on certain multi monitor configurations. With these 3 patches, you're getting the same effect as reverting the aforementioned patches, but it makes the reverted sequence available only for Steam deck hardware.

--

Regards,
Jay
________________________________
From: Guilherme G. Piccoli <gpiccoli at igalia.com>
Sent: Tuesday, July 11, 2023 7:15 PM
To: Pillai, Aurabindo <Aurabindo.Pillai at amd.com>; Deucher, Alexander <Alexander.Deucher at amd.com>
Cc: amd-gfx at lists.freedesktop.org <amd-gfx at lists.freedesktop.org>; Koenig, Christian <Christian.Koenig at amd.com>; Pan, Xinhui <Xinhui.Pan at amd.com>; dri-devel at lists.freedesktop.org <dri-devel at lists.freedesktop.org>; kernel-dev at igalia.com <kernel-dev at igalia.com>; cristian.ciocaltea at collabora.com <cristian.ciocaltea at collabora.com>; André Almeida <andrealmeid at igalia.com>; Melissa Wen <mwen at igalia.com>; Siqueira, Rodrigo <Rodrigo.Siqueira at amd.com>
Subject: Re: [PATCH] Revert "drm/amd/display: Program OTG vtotal min/max selectors unconditionally for DCN1+"

On 11/07/2023 15:22, Aurabindo Pillai wrote:
> [...]
> Hi,
>
> Sorry for the delayed response, this patch went unnoticed. This revert would break asics. Could you try the attached patch without reverting this one ?

Hi Aurabindo, thanks for your response!

I've tried kernel 6.5-rc1, and it seems the issue is present, due to the
patch being merged on Linus tree [as 1598fc576420 ("drm/amd/display:
Program OTG vtotal min/max selectors unconditionally for DCN1+")].

Then, I tried both your attached patches on top of that, and
unfortunately, the behavior is the same: Steam Deck doesn't boot with
graphics, and we can see the single error "amdgpu 0000:04:00.0: [drm]
*ERROR* [CRTC:67:crtc-0] flip_done timed out" on dmesg.

Do you / Alex think we could get this revert for 6.5-rc2, so at least we
could boot mainline there while the issue is handled? It would be an
intermediate fix. You mentioned it breaks some asics, but did they work
until now, without your patch?

Thanks,


Guilherme
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