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

[kalyan_t@xxxxxxxxxxxxxx]

On 2021-04-01 19:01, Dmitry Baryshkov wrote:
> On Thu, 1 Apr 2021 at 16:19, <kalyan_t@xxxxxxxxxxxxxx> wrote:
> > On 2021-04-01 07:37, Dmitry Baryshkov wrote:
> > > 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/
> >
> > Hi Dmitry,
> >
> > https://lore.kernel.org/linux-arm-msm/20210401020533.3956787-2-dmitry.baryshkov@xxxxxxxxxx/
> >
> > you need to add clk_inefficiency_factor, bw_inefficiency_factor in the
> > catalogue for the new
> > targets where bw scaling is being enabled. please reuse sc7180 values.
>
> Done in patch 1 in that series.
got it.

> > secondly, the AXI clock needs to be moved from mdss to mdp device like
> > as in sc7180 dt if its not done already.
>
> Is this enough:
> sm8250 has <&gcc GCC_DISP_HF_AXI_CLK> both in mdss and mdp nodes
> sdm845 has <&gcc GCC_DISP_AXI_CLK> in mdss node and <&dispcc
> DISP_CC_MDSS_AXI_CLK> in the mdp node.
>
> Since there is no BW vote in mdss, we need to move the AXI clock ON to 
> mdp node.

for sm8250
remove GCC_DISP_HF_AXI_CLK from mdss device and add it in mdp device.

for sdm845
remove GCC_DISP_AXI_CLK from mdss device and add it in mdp device before 
we turn on DISP_CC_MDSS_AXI_CLK, i.e as first item.

> > lastly, if you are planning to remove the static votes from dpu_mdss, 
> > do
> > you also want to move the
> > interconnect paths from mdss device to mdp device in the dt ?
>
> I have no strong opinion on this. So far I did not change dt to be
> compatible with the current device trees.
>
> > Thanks,
> > Kalyan
> >
> > >
> > >>
> > >>>>
> > >>>> Reported-by: Steev Klimaszewski <steev@xxxxxxxx>
> > >>
> > >> Please add Fixes: tag as well
> > Adding Fixes tag above my sign-off, should i push another version or 
> > can
> > it be picked from here ?
> >
> > Fixes: 627dc55c273d ("drm/msm/disp/dpu1: icc path needs to be set 
> > before
> > dpu runtime resume")
> > >>
> > >>>> 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