Re: [v1] drm/msm/disp/dpu1: fix warn stack reported during dpu resume

[Dmitry Baryshkov]

On 01/04/2021 01:47, Rob Clark wrote:
> On Wed, Mar 31, 2021 at 9:03 AM Dmitry Baryshkov
> <dmitry.baryshkov@xxxxxxxxxx> wrote:
> > On 31/03/2021 14:27, Kalyan Thota wrote:
> > > WARN_ON was introduced by the below commit to catch runtime resumes
> > > that are getting triggered before icc path was set.
> > >
> > > "drm/msm/disp/dpu1: icc path needs to be set before dpu runtime resume"
> > >
> > > For the targets where the bw scaling is not enabled, this WARN_ON is
> > > a false alarm. Fix the WARN condition appropriately.
> >
> > Should we change all DPU targets to use bw scaling to the mdp from the
> > mdss nodes? The limitation to sc7180 looks artificial.
>
> yes, we should, this keeps biting us on 845

Done, 
https://lore.kernel.org/linux-arm-msm/20210401020533.3956787-2-dmitry.baryshkov@xxxxxxxxxx/

> > > Reported-by: Steev Klimaszewski <steev@xxxxxxxx>
>
> Please add Fixes: tag as well
>
> > > Signed-off-by: Kalyan Thota <kalyan_t@xxxxxxxxxxxxxx>
> > > ---
> > >    drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c  |  8 +++++---
> > >    drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h  |  9 +++++++++
> > >    drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c | 11 ++++++-----
> > >    3 files changed, 20 insertions(+), 8 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> > > index cab387f..0071a4d 100644
> > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> > > @@ -294,6 +294,9 @@ static int dpu_kms_parse_data_bus_icc_path(struct dpu_kms *dpu_kms)
> > >        struct icc_path *path1;
> > >        struct drm_device *dev = dpu_kms->dev;
> > >
> > > +     if (!dpu_supports_bw_scaling(dev))
> > > +             return 0;
> > > +
> > >        path0 = of_icc_get(dev->dev, "mdp0-mem");
> > >        path1 = of_icc_get(dev->dev, "mdp1-mem");
> > >
> > > @@ -934,8 +937,7 @@ static int dpu_kms_hw_init(struct msm_kms *kms)
> > >                DPU_DEBUG("REG_DMA is not defined");
> > >        }
> > >
> > > -     if (of_device_is_compatible(dev->dev->of_node, "qcom,sc7180-mdss"))
> > > -             dpu_kms_parse_data_bus_icc_path(dpu_kms);
> > > +     dpu_kms_parse_data_bus_icc_path(dpu_kms);
> > >
> > >        pm_runtime_get_sync(&dpu_kms->pdev->dev);
> > >
> > > @@ -1198,7 +1200,7 @@ static int __maybe_unused dpu_runtime_resume(struct device *dev)
> > >
> > >        ddev = dpu_kms->dev;
> > >
> > > -     WARN_ON(!(dpu_kms->num_paths));
> > > +     WARN_ON((dpu_supports_bw_scaling(ddev) && !dpu_kms->num_paths));
> > >        /* Min vote of BW is required before turning on AXI clk */
> > >        for (i = 0; i < dpu_kms->num_paths; i++)
> > >                icc_set_bw(dpu_kms->path[i], 0, Bps_to_icc(MIN_IB_BW));
> > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
> > > index d6717d6..f7bcc0a 100644
> > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
> > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h
> > > @@ -154,6 +154,15 @@ struct vsync_info {
> > >
> > >    #define to_dpu_global_state(x) container_of(x, struct dpu_global_state, base)
> > >
> > > +/**
> > > + * dpu_supports_bw_scaling: returns true for drivers that support bw scaling.
> > > + * @dev: Pointer to drm_device structure
> > > + */
> > > +static inline int dpu_supports_bw_scaling(struct drm_device *dev)
> > > +{
> > > +     return of_device_is_compatible(dev->dev->of_node, "qcom,sc7180-mdss");
> > > +}
> > > +
> > >    /* Global private object state for tracking resources that are shared across
> > >     * multiple kms objects (planes/crtcs/etc).
> > >     */
> > > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c
> > > index cd40788..8cd712c 100644
> > > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c
> > > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_mdss.c
> > > @@ -41,6 +41,9 @@ static int dpu_mdss_parse_data_bus_icc_path(struct drm_device *dev,
> > >        struct icc_path *path0 = of_icc_get(dev->dev, "mdp0-mem");
> > >        struct icc_path *path1 = of_icc_get(dev->dev, "mdp1-mem");
> > >
> > > +     if (dpu_supports_bw_scaling(dev))
> > > +             return 0;
> > > +
> > >        if (IS_ERR_OR_NULL(path0))
> > >                return PTR_ERR_OR_ZERO(path0);
> > >
> > > @@ -276,11 +279,9 @@ int dpu_mdss_init(struct drm_device *dev)
> > >
> > >        DRM_DEBUG("mapped mdss address space @%pK\n", dpu_mdss->mmio);
> > >
> > > -     if (!of_device_is_compatible(dev->dev->of_node, "qcom,sc7180-mdss")) {
> > > -             ret = dpu_mdss_parse_data_bus_icc_path(dev, dpu_mdss);
> > > -             if (ret)
> > > -                     return ret;
> > > -     }
> > > +     ret = dpu_mdss_parse_data_bus_icc_path(dev, dpu_mdss);
> > > +     if (ret)
> > > +             return ret;
> > >
> > >        mp = &dpu_mdss->mp;
> > >        ret = msm_dss_parse_clock(pdev, mp);
> >
> >
> > --
> > With best wishes
> > Dmitry


--
With best wishes
Dmitry