[Freedreno] [PATCH 3/3] drm/msm/dpu: add support for clk and bw scaling for display

[Amit Pundir]

Hi Kalyan,

On Tue, 24 Nov 2020 at 18:27, <kalyan_t at codeaurora.org> wrote:
>
> On 2020-11-08 23:25, Amit Pundir wrote:
> > On Tue, 4 Aug 2020 at 21:09, Rob Clark <robdclark at gmail.com> wrote:
> >>
> >> On Thu, Jul 16, 2020 at 4:36 AM Kalyan Thota <kalyan_t at codeaurora.org>
> >> wrote:
> >> >
> >> > This change adds support to scale src clk and bandwidth as
> >> > per composition requirements.
> >> >
> >> > Interconnect registration for bw has been moved to mdp
> >> > device node from mdss to facilitate the scaling.
> >> >
> >> > Changes in v1:
> >> >  - Address armv7 compilation issues with the patch (Rob)
> >> >
> >> > Signed-off-by: Kalyan Thota <kalyan_t at codeaurora.org>
> >>
> >> Reviewed-by: Rob Clark <robdclark at chromium.org>
> >>
> >
> > Hi Kalyan, Rob,
> >
> > This patch broke the display on the PocoF1 phone
> > (sdm845-xiaomi-beryllium.dts) running AOSP.
> > I can boot to UI but the display is frozen soon after that and
> > dmesg is full of following errors:
> >
> > [drm:dpu_core_perf_crtc_update:397] [dpu error]crtc-65: failed to
> > update bus bw vote
> > [drm:dpu_core_perf_crtc_check:203] [dpu error]exceeds bandwidth:
> > 7649746kb > 6800000kb
> > [drm:dpu_crtc_atomic_check:969] [dpu error]crtc65 failed performance
> > check -7
> > [drm:dpu_core_perf_crtc_check:203] [dpu error]exceeds bandwidth:
> > 7649746kb > 6800000kb
> > [drm:dpu_crtc_atomic_check:969] [dpu error]crtc65 failed performance
> > check -7
> > [drm:dpu_core_perf_crtc_check:203] [dpu error]exceeds bandwidth:
> > 7649746kb > 6800000kb
> > [drm:dpu_crtc_atomic_check:969] [dpu error]crtc65 failed performance
> > check -7
> >
> > Here is the full dmesg https://pastebin.ubuntu.com/p/PcSdNgMnYw/.
> > Georgi pointed out following patch but it didn't help,
> > https://lore.kernel.org/dri-devel/20201027102304.945424-1-dmitry.baryshkov@linaro.org/
> > Am I missing any other followup fix?
> >
> > Regards,
> > Amit Pundir
> > __
>
> Hi Amit,
>
> Apologies for the delay.

No worries at all.

>
> I have gone through the logs and referred to the below panel file for
> the timings.
> https://github.com/Matheus-Garbelini/Kernel-Sphinx-Pocophone-F1/blob/master/arch/arm64/boot/dts/qcom/dsi-panel-tianma-fhd-nt36672a-video.dtsi
>
> if the above is correct file, then below could be the possible root
> cause.
>
> The panel back porch and pw is less and it is causing the prefill bw
> requirement to shoot up per layer as currently we are not considering
> front porch in the calculation. can you please try the attached patch in
> the email as a solution and provide me the feedback, i'll post it as a
> formal change.

The attached patch worked for me. Thanks a lot for looking closely
into this issue.

Regards,
Amit Pundir

>
> Thanks,
> Kalyan
>
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