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Date:   Fri, 02 Apr 2021 17:12:25 +0530
From:   kalyan_t@codeaurora.org
To:     Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Cc:     Rob Clark <robdclark@gmail.com>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        Krishna Manikandan <mkrishn@codeaurora.org>,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        Daniel Hung-yu Wu <hywu@google.com>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        dri-devel <dri-devel@lists.freedesktop.org>,
        Douglas Anderson <dianders@chromium.org>,
        Matthias Kaehlcke <mka@google.com>,
        Michelle Dean <midean@google.com>,
        Steev Klimaszewski <steev@kali.org>,
        freedreno <freedreno@lists.freedesktop.org>, y@qualcomm.com
Subject: Re: [Freedreno] [v1] drm/msm/disp/dpu1: fix warn stack reported
 during dpu resume
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On 2021-04-01 19:01, Dmitry Baryshkov wrote:
> On Thu, 1 Apr 2021 at 16:19, <kalyan_t@codeaurora.org> 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@linaro.org> 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@linaro.org/
>> 
>> Hi Dmitry,
>> 
>> https://lore.kernel.org/linux-arm-msm/20210401020533.3956787-2-dmitry.baryshkov@linaro.org/
>> 
>> 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@kali.org>
>> >>
>> >> 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@codeaurora.org>
>> >>>> ---
>> >>>>    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