linux-kernel - Re: [RFC] drm/msm/adreno: Balance pm

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Date:   Wed, 22 Feb 2023 12:07:20 +0100
From:   Johan Hovold <johan@...nel.org>
To:     Rob Clark <robdclark@...il.com>
Cc:     Bjorn Andersson <quic_bjorande@...cinc.com>,
        Abhinav Kumar <quic_abhinavk@...cinc.com>,
        Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
        Akhil P Oommen <quic_akhilpo@...cinc.com>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Konrad Dybcio <konrad.dybcio@...ainline.org>,
        linux-arm-msm@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        freedreno@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC] drm/msm/adreno: Balance pm_runtime enable

On Fri, Feb 10, 2023 at 08:10:00AM -0800, Rob Clark wrote:
> On Fri, Feb 3, 2023 at 10:12 AM Bjorn Andersson
> <quic_bjorande@...cinc.com> wrote:
> >
> > When any of the components in the mdss hierarchy fails to bind,
> > previously bound components are being unbound again.
> >
> > One such case happens when the DP controller fails to find its bridge or
> > panel, where adreno_unbind() will be invoked without adreno_load_gpu()
> > being called to invoke pm_runtime_enable().
> >
> > The result is that once everything is bound the pm_runtime_get_sync()
> > call find the power-domain to have a positive disable_depth, fails
> > with -EACCESS and prevents the GPU device to be powered up.
> >
> > Move the pm_runtime_enable() to adreno_bind(), in order to balance it
> > with any calls to adreno_unbind().
> 
> I think instead we want to move where the pm_runtime_disable() is..
> since pm_runtime_enable() was moved because we can't actually enable
> runpm until we have GMU firmware

Here's a fix for this issue which does not move pm_runtime_enable() from
first open():

	https://lore.kernel.org/lkml/20230221101430.14546-1-johan+linaro@kernel.org/

Johan