linux-kernel - Re: [PATCH 0/2] Add quirk to disable PSR 2 on Tongfang PHxTxX1 and PHxTQx1

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Date:   Fri, 24 Feb 2023 06:45:53 +0000
From:   "Hogander, Jouni" <jouni.hogander@...el.com>
To:     "Souza, Jose" <jose.souza@...el.com>,
        "Santa Cruz, Diego" <Diego.SantaCruz@...netix.com>,
        "wse@...edocomputers.com" <wse@...edocomputers.com>,
        "ville.syrjala@...ux.intel.com" <ville.syrjala@...ux.intel.com>,
        "Vivi, Rodrigo" <rodrigo.vivi@...el.com>,
        "joonas.lahtinen@...ux.intel.com" <joonas.lahtinen@...ux.intel.com>,
        "Kahola, Mika" <mika.kahola@...el.com>,
        "airlied@...il.com" <airlied@...il.com>,
        "tvrtko.ursulin@...ux.intel.com" <tvrtko.ursulin@...ux.intel.com>,
        "intel-gfx@...ts.freedesktop.org" <intel-gfx@...ts.freedesktop.org>,
        "dri-devel@...ts.freedesktop.org" <dri-devel@...ts.freedesktop.org>,
        "daniel@...ll.ch" <daniel@...ll.ch>,
        "jani.nikula@...ux.intel.com" <jani.nikula@...ux.intel.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "De Marchi, Lucas" <lucas.demarchi@...el.com>
Subject: Re: [PATCH 0/2] Add quirk to disable PSR 2 on Tongfang PHxTxX1 and
 PHxTQx1

On Thu, 2023-02-23 at 20:02 +0100, Werner Sembach wrote:
> 
> Am 23.02.23 um 19:56 schrieb Werner Sembach:
> > 
> > Am 23.02.23 um 19:26 schrieb Hogander, Jouni:
> > > On Wed, 2023-02-22 at 15:17 +0100, Werner Sembach wrote:
> > > > On these Barebones PSR 2 is recognized as supported but is very
> > > > buggy:
> > > > - Upper third of screen does sometimes not updated, resulting
> > > > in
> > > > disappearing cursors or ghosts of already closed Windows saying
> > > > behind.
> > > > - Approximately 40 px from the bottom edge a 3 pixel wide strip
> > > > of
> > > > randomly
> > > > colored pixels is flickering.
> > > > 
> > > > PSR 1 is working fine however.
> > > > 
> > > > This patchset introduces a new quirk to disable PSR 2
> > > > specifically on
> > > > known
> > > > buggy devices and applies it to the Tongfang PHxTxX1 and
> > > > PHxTQx1
> > > > barebones.
> > > I've been thinking something similar as there is still at least
> > > one
> > > issue which seems to be like panel side issue:
> > > 
> > > https://gitlab.freedesktop.org/drm/intel/-/issues/7836
> > > 
> > > Did you considered dpcd_quirk_list in
> > > drivers/gpu/drm/drm_dp_helper.c?
> > > 
> > > I'm not sure which one is more correct though...
> > Imho, since the proper fix lies within the Intel driver the quirk
> > should also 
> > lie within the Intel driver, because even if the panel has the same
> > problem 
> > combined with an AMD or NVIDIA card the proper fix for them will
> > most likely 
> > be land in the same kernel version. So there could be a period
> > where you no 
> > longer want the quirk for devices combining the panel with an Intel
> > gpu but 
> > still with an AMD GPU or vice versa.
> *the proper fix for them will most likely not be in the same kernel
> version.

Yeah, you are right here. Let's target fixing rootcause for your setup.
First patch from your set could be anyways used for issue mentioned
above.

> > > 
> > > > Signed-off-by: Werner Sembach <wse@...edocomputers.com>
> > > > Cc: <stable@...r.kernel.org>
> > > > 
> > > > 

BR,

Jouni Högander