linux-kernel - Re: [PATCH] drm/msm/a6xx: fix bogus hwcg register updates

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Message-ID: <CACSVV039g9CcAKhtMAwn=hH4hMT2nV77vxiasgUSFF-sn=+JgA@mail.gmail.com>
Date: Wed, 21 Jan 2026 08:59:51 -0800
From: Rob Clark <rob.clark@....qualcomm.com>
To: Johan Hovold <johan@...nel.org>
Cc: Sean Paul <sean@...rly.run>, Konrad Dybcio <konradybcio@...nel.org>,
        Akhil P Oommen <akhilpo@....qualcomm.com>,
        Dmitry Baryshkov <lumag@...nel.org>,
        Abhinav Kumar <abhinav.kumar@...ux.dev>,
        Jessica Zhang <jesszhan0024@...il.com>,
        Marijn Suijten <marijn.suijten@...ainline.org>,
        Bjorn Andersson <andersson@...nel.org>, linux-arm-msm@...r.kernel.org,
        dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH] drm/msm/a6xx: fix bogus hwcg register updates

On Wed, Jan 21, 2026 at 7:17 AM Johan Hovold <johan@...nel.org> wrote:
>
> On Wed, Jan 14, 2026 at 09:56:12AM +0100, Johan Hovold wrote:
> > On Sun, Dec 21, 2025 at 05:45:52PM +0100, Johan Hovold wrote:
> > > The hw clock gating register sequence consists of register value pairs
> > > that are written to the GPU during initialisation.
> > >
> > > The a690 hwcg sequence has two GMU registers in it that used to amount
> > > to random writes in the GPU mapping, but since commit 188db3d7fe66
> > > ("drm/msm/a6xx: Rebase GMU register offsets") they trigger a fault as
> > > the updated offsets now lie outside the mapping. This in turn breaks
> > > boot of machines like the Lenovo ThinkPad X13s.
> > >
> > > Note that the updates of these GMU registers is already taken care of
> > > properly since commit 40c297eb245b ("drm/msm/a6xx: Set GMU CGC
> > > properties on a6xx too"), but for some reason these two entries were
> > > left in the table.
> > >
> > > Fixes: 5e7665b5e484 ("drm/msm/adreno: Add Adreno A690 support")
> > > Cc: stable@...r.kernel.org  # 6.5
> > > Cc: Bjorn Andersson <andersson@...nel.org>
> > > Cc: Konrad Dybcio <konradybcio@...nel.org>
> > > Signed-off-by: Johan Hovold <johan@...nel.org>
> > > ---
> >
> > This one does not seem to have been applied yet despite fixing a
> > critical regression in 6.19-rc1. I guess I could have highlighted that
> > further by also including:
> >
> > Fixes: 188db3d7fe66 ("drm/msm/a6xx: Rebase GMU register offsets")
> >
> > I realise some delays are expected around Christmas, but can you please
> > try to get this fix to Linus now that everyone should be back again?
>
> I haven't received any reply so was going to send another reminder, but
> I noticed now that this patch was merged to the msm-next branch last
> week.
>
> Since it fixes a regression in 6.19-rc1 it needs to go to Linus this
> cycle and I would have assumed it should have be merged to msm-fixes.
>
> (MSM) DRM works in mysterious ways, so can someone please confirm that
> this regression fix is heading into mainline for 6.19-final?

Sorry, mesa 26.0 branchpoint this week so I've not had much time for
kernel for last few weeks and didn't have time for a 2nd msm-fixes PR.
But with fixes/cc tags it should be picked into 6.19.y

BR,
-R