[PATCH 14/17] drm/msm/dpu: modify encoder programming for CDM over DP

Dmitry Baryshkov dmitry.baryshkov at linaro.org
Mon Jan 29 23:44:04 UTC 2024


On Mon, 29 Jan 2024 at 09:08, Abhinav Kumar <quic_abhinavk at quicinc.com> wrote:
>
> On 1/28/2024 10:12 PM, Dmitry Baryshkov wrote:
> > On Mon, 29 Jan 2024 at 07:03, Abhinav Kumar <quic_abhinavk at quicinc.com> wrote:
> >>
> >>
> >>
> >> On 1/28/2024 7:42 PM, Dmitry Baryshkov wrote:
> >>> On Mon, 29 Jan 2024 at 04:58, Abhinav Kumar <quic_abhinavk at quicinc.com> wrote:
> >>>>
> >>>>
> >>>>
> >>>> On 1/27/2024 9:55 PM, Dmitry Baryshkov wrote:
> >>>>> On Sun, 28 Jan 2024 at 07:48, Paloma Arellano <quic_parellan at quicinc.com> wrote:
> >>>>>>
> >>>>>>
> >>>>>> On 1/25/2024 1:57 PM, Dmitry Baryshkov wrote:
> >>>>>>> On 25/01/2024 21:38, Paloma Arellano wrote:
> >>>>>>>> Adjust the encoder format programming in the case of video mode for DP
> >>>>>>>> to accommodate CDM related changes.
> >>>>>>>>
> >>>>>>>> Signed-off-by: Paloma Arellano <quic_parellan at quicinc.com>
> >>>>>>>> ---
> >>>>>>>>      drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c   | 16 +++++++++
> >>>>>>>>      drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h   |  8 +++++
> >>>>>>>>      .../drm/msm/disp/dpu1/dpu_encoder_phys_vid.c  | 35 ++++++++++++++++---
> >>>>>>>>      drivers/gpu/drm/msm/dp/dp_display.c           | 12 +++++++
> >>>>>>>>      drivers/gpu/drm/msm/msm_drv.h                 |  9 ++++-
> >>>>>>>>      5 files changed, 75 insertions(+), 5 deletions(-)
> >>>>>>>>
> >>>>>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> >>>>>>>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> >>>>>>>> index b0896814c1562..99ec53446ad21 100644
> >>>>>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> >>>>>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> >>>>>>>> @@ -222,6 +222,22 @@ static u32 dither_matrix[DITHER_MATRIX_SZ] = {
> >>>>>>>>          15, 7, 13, 5, 3, 11, 1, 9, 12, 4, 14, 6, 0, 8, 2, 10
> >>>>>>>>      };
> >>>>>>>>      +u32 dpu_encoder_get_drm_fmt(const struct drm_encoder *drm_enc,
> >>>>>>>> const struct drm_display_mode *mode)
> >>>>>>>> +{
> >>>>>>>> +    const struct dpu_encoder_virt *dpu_enc;
> >>>>>>>> +    const struct msm_display_info *disp_info;
> >>>>>>>> +    struct msm_drm_private *priv;
> >>>>>>>> +
> >>>>>>>> +    dpu_enc = to_dpu_encoder_virt(drm_enc);
> >>>>>>>> +    disp_info = &dpu_enc->disp_info;
> >>>>>>>> +    priv = drm_enc->dev->dev_private;
> >>>>>>>> +
> >>>>>>>> +    if (disp_info->intf_type == INTF_DP &&
> >>>>>>>> + msm_dp_is_yuv_420_enabled(priv->dp[disp_info->h_tile_instance[0]],
> >>>>>>>> mode))
> >>>>>>>
> >>>>>>> This should not require interacting with DP. If we got here, we must
> >>>>>>> be sure that 4:2:0 is supported and can be configured.
> >>>>>> Ack. Will drop this function and only check for if the mode is YUV420.
> >>>>>>>
> >>>>>>>> +        return DRM_FORMAT_YUV420;
> >>>>>>>> +
> >>>>>>>> +    return DRM_FORMAT_RGB888;
> >>>>>>>> +}
> >>>>>>>>        bool dpu_encoder_is_widebus_enabled(const struct drm_encoder
> >>>>>>>> *drm_enc)
> >>>>>>>>      {
> >>>>>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> >>>>>>>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> >>>>>>>> index 7b4afa71f1f96..62255d0aa4487 100644
> >>>>>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> >>>>>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h
> >>>>>>>> @@ -162,6 +162,14 @@ int dpu_encoder_get_vsync_count(struct
> >>>>>>>> drm_encoder *drm_enc);
> >>>>>>>>       */
> >>>>>>>>      bool dpu_encoder_is_widebus_enabled(const struct drm_encoder
> >>>>>>>> *drm_enc);
> >>>>>>>>      +/**
> >>>>>>>> + * dpu_encoder_get_drm_fmt - return DRM fourcc format
> >>>>>>>> + * @drm_enc:    Pointer to previously created drm encoder structure
> >>>>>>>> + * @mode:    Corresponding drm_display_mode for dpu encoder
> >>>>>>>> + */
> >>>>>>>> +u32 dpu_encoder_get_drm_fmt(const struct drm_encoder *drm_enc,
> >>>>>>>> +                const struct drm_display_mode *mode);
> >>>>>>>> +
> >>>>>>>>      /**
> >>>>>>>>       * dpu_encoder_get_crc_values_cnt - get number of physical encoders
> >>>>>>>> contained
> >>>>>>>>       *    in virtual encoder that can collect CRC values
> >>>>>>>> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
> >>>>>>>> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
> >>>>>>>> index e284bf448bdda..a1dde0ff35dc8 100644
> >>>>>>>> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
> >>>>>>>> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c
> >>>>>>>> @@ -234,6 +234,7 @@ static void
> >>>>>>>> dpu_encoder_phys_vid_setup_timing_engine(
> >>>>>>>>      {
> >>>>>>>>          struct drm_display_mode mode;
> >>>>>>>>          struct dpu_hw_intf_timing_params timing_params = { 0 };
> >>>>>>>> +    struct dpu_hw_cdm *hw_cdm;
> >>>>>>>>          const struct dpu_format *fmt = NULL;
> >>>>>>>>          u32 fmt_fourcc = DRM_FORMAT_RGB888;
> >>>>>>>>          unsigned long lock_flags;
> >>>>>>>> @@ -254,17 +255,26 @@ static void
> >>>>>>>> dpu_encoder_phys_vid_setup_timing_engine(
> >>>>>>>>          DPU_DEBUG_VIDENC(phys_enc, "enabling mode:\n");
> >>>>>>>>          drm_mode_debug_printmodeline(&mode);
> >>>>>>>>      -    if (phys_enc->split_role != ENC_ROLE_SOLO) {
> >>>>>>>> +    hw_cdm = phys_enc->hw_cdm;
> >>>>>>>> +    if (hw_cdm) {
> >>>>>>>> +        intf_cfg.cdm = hw_cdm->idx;
> >>>>>>>> +        fmt_fourcc = dpu_encoder_get_drm_fmt(phys_enc->parent, &mode);
> >>>>>>>> +    }
> >>>>>>>> +
> >>>>>>>> +    if (phys_enc->split_role != ENC_ROLE_SOLO ||
> >>>>>>>> +        dpu_encoder_get_drm_fmt(phys_enc->parent, &mode) ==
> >>>>>>>> DRM_FORMAT_YUV420) {
> >>>>>>>>              mode.hdisplay >>= 1;
> >>>>>>>>              mode.htotal >>= 1;
> >>>>>>>>              mode.hsync_start >>= 1;
> >>>>>>>>              mode.hsync_end >>= 1;
> >>>>>>>> +        mode.hskew >>= 1;
> >>>>>>>
> >>>>>>> Separate patch.
> >>>>>> Ack.
> >>>>>>>
> >>>>>>>>                DPU_DEBUG_VIDENC(phys_enc,
> >>>>>>>> -            "split_role %d, halve horizontal %d %d %d %d\n",
> >>>>>>>> +            "split_role %d, halve horizontal %d %d %d %d %d\n",
> >>>>>>>>                  phys_enc->split_role,
> >>>>>>>>                  mode.hdisplay, mode.htotal,
> >>>>>>>> -            mode.hsync_start, mode.hsync_end);
> >>>>>>>> +            mode.hsync_start, mode.hsync_end,
> >>>>>>>> +            mode.hskew);
> >>>>>>>>          }
> >>>>>>>>            drm_mode_to_intf_timing_params(phys_enc, &mode, &timing_params);
> >>>>>>>> @@ -412,8 +422,15 @@ static int dpu_encoder_phys_vid_control_vblank_irq(
> >>>>>>>>      static void dpu_encoder_phys_vid_enable(struct dpu_encoder_phys
> >>>>>>>> *phys_enc)
> >>>>>>>>      {
> >>>>>>>>          struct dpu_hw_ctl *ctl;
> >>>>>>>> +    struct dpu_hw_cdm *hw_cdm;
> >>>>>>>> +    const struct dpu_format *fmt = NULL;
> >>>>>>>> +    u32 fmt_fourcc = DRM_FORMAT_RGB888;
> >>>>>>>>            ctl = phys_enc->hw_ctl;
> >>>>>>>> +    hw_cdm = phys_enc->hw_cdm;
> >>>>>>>> +    if (hw_cdm)
> >>>>>>>> +        fmt_fourcc = dpu_encoder_get_drm_fmt(phys_enc->parent,
> >>>>>>>> &phys_enc->cached_mode);
> >>>>>>>> +    fmt = dpu_get_dpu_format(fmt_fourcc);
> >>>>>>>>            DPU_DEBUG_VIDENC(phys_enc, "\n");
> >>>>>>>>      @@ -422,6 +439,8 @@ static void dpu_encoder_phys_vid_enable(struct
> >>>>>>>> dpu_encoder_phys *phys_enc)
> >>>>>>>>            dpu_encoder_helper_split_config(phys_enc,
> >>>>>>>> phys_enc->hw_intf->idx);
> >>>>>>>>      +    dpu_encoder_helper_phys_setup_cdm(phys_enc, fmt,
> >>>>>>>> CDM_CDWN_OUTPUT_HDMI);
> >>>>>>>
> >>>>>>> If there is no CDM, why do we need to call this?
> >>>>>> Inside of dpu_encoder_helper_phys_setup_cdm(), there's a check to see if
> >>>>>> there is a hw_cdm. If there is not, then it immediately exits the function.
> >>>>>>>
> >>>>>>>> +
> >>>>>>>>          dpu_encoder_phys_vid_setup_timing_engine(phys_enc);
> >>>>>>>>            /*
> >>>>>>>> @@ -437,7 +456,15 @@ static void dpu_encoder_phys_vid_enable(struct
> >>>>>>>> dpu_encoder_phys *phys_enc)
> >>>>>>>>          if (ctl->ops.update_pending_flush_merge_3d &&
> >>>>>>>> phys_enc->hw_pp->merge_3d)
> >>>>>>>>              ctl->ops.update_pending_flush_merge_3d(ctl,
> >>>>>>>> phys_enc->hw_pp->merge_3d->idx);
> >>>>>>>>      -    if (ctl->ops.update_pending_flush_periph &&
> >>>>>>>> phys_enc->hw_intf->cap->type == INTF_DP)
> >>>>>>>> +    if (ctl->ops.update_pending_flush_cdm && phys_enc->hw_cdm)
> >>>>>>>> +        ctl->ops.update_pending_flush_cdm(ctl, hw_cdm->idx);
> >>>>>>>> +
> >>>>>>>> +    /*
> >>>>>>>> +     * Peripheral flush must be updated whenever flushing SDP
> >>>>>>>> packets is needed.
> >>>>>>>> +     * SDP packets are required for any YUV format (YUV420, YUV422,
> >>>>>>>> YUV444).
> >>>>>>>> +     */
> >>>>>>>> +    if (ctl->ops.update_pending_flush_periph &&
> >>>>>>>> phys_enc->hw_intf->cap->type == INTF_DP &&
> >>>>>>>> +        phys_enc->hw_cdm)
> >>>>>>>>              ctl->ops.update_pending_flush_periph(ctl,
> >>>>>>>> phys_enc->hw_intf->idx);
> >>>>>>>
> >>>>>>> Should there be a flush if we are switching from YUV 420 to RGB mode?
> >>>>>> We only need to flush for the sdp packet, but for msa we do not need to
> >>>>>> flush.
> >>>>>
> >>>>> What about having SDP with RGB as colorimetry? In other words, if
> >>>>> there is a decision point, this one looks incorrect.
> >>>>>
> >>>>
> >>>> There are two ways to do it:
> >>>>
> >>>> 1) Use SDP for both RGB and YUV as that supports both. If we implement
> >>>> this policy, then what you are asking for is correct that we will need
> >>>> SDP even to switch back to RGB. But to implement this we will also need
> >>>> to have some sort of state management in the encoder layer about what is
> >>>> the current encoder fmt Vs what is the prev fmt and then trigger
> >>>> peripheral flush only during transitions from RGB to YUV and vice-versa
> >>>>
> >>>> 2) Use SDP only for YUV because MSA does not support YUV formats and use
> >>>> MSA for RGB
> >>>>
> >>>> We decided to implement (2) and there is no significant impact of
> >>>> switching between MSA and SDPs but state management becomes easier.
> >>>
> >>> Yes. However as you wrote, there might be other usecases concerning
> >>> SDP. Having this in mind, it sounds like the driver should decide
> >>> whether to flush peripheral at a different place (when the SDP
> >>> infoframe is being updated?). And the dpu_encoder_phys_vid_enable()
> >>> should use this previous decision. Maybe this should be a part of
> >>> msm_dp_ API, something like msm_dp_needs_peripheral_flush()?
> >>>
> >>
> >> Correct. The decision to flush peripheral or not certainly comes from
> >> the peripheral itself . In this case its DP.
> >>
> >> I think perhaps the usage of hw_cdm here makes it hard to understand
> >> that but the idea behind this was that in the change "drm/msm/dpu:
> >> reserve CDM blocks for DP if mode is YUV420 ", hw_cdm is assigned only
> >> if msm_dp_is_yuv_420_enabled() returns true.
> >
> > Yes.
> >
> >>
> >> So in some sense, the API you are asking for is already
> >> msm_dp_is_yuv_420_enabled() but we can rename that to
> >> msm_dp_needs_periph_flush().
> >
> > No. This leaks details. We might need peripheral flush for other
> > reasons. So this decision should be made inside the DP driver.
> > BTW, is there a need to flush-peripheral each time the INTF gets
> > enabled? When some bits of configuration were updated (like SDP
> > infoframe or CDM config)?
> >
>
> Not really leaking any details. Interface decides when DPU's flush bit
> needs to be invoked. All the conditions needing the flush can be
> absorbed within msm_dp_needs_periph_flush() which will be within DP
> driver. So I dont see any issue with that.

As long as we have two distinct functions: msm_dp_needs_periph_flush()
and msm_dp_is_yuv420_enabled(), it's fine with me.

>
> The peripheral flush needs to be invoked whenever SDP/PPS packets need
> to be sent out at the very least. Those are the two main use-cases so far.
>
> Not necessarily each time the INTF is enabled.
>
> But ....
>
> For PPS, we would typically enable DSC from the first frame itself and
> we dont support dynamically turning DSC ON/OFF so its a fair assumption
> that we need to the peripheral flush for DSC only during enable.
>
> For SDP, so today we enforce a modeset when we switch from a case of
> needing cdm / not needing cdm and vice-versa. So even this use-case
> should be accompanied by a disable()/enable().

My point was that there might be other changes to the SDP infoframe.

>
> So are you suggesting that we unconditionally just do peripheral_flush
> from enable()?
>
> I need to do some checking but maybe ....

This might be an option too. I don't know what delays / issues it can cause.

>
> >>
> >> The issue here is the phys layer cannot call msm_dp_is_yuv_420_enabled()
> >> so its kind of round-about by checking hw_cdm.
> >
> > Which maybe means that I should finish phys / encoder rework.
> >
>
> Ugh no. Not another rework just for this.

It is pending for the CTL flush story.

>
> >>
> >> The check is not entirely wrong because for DP, we need hw_cdm for all
> >> YUV formats and not just 420 but the relationship is maybe not clear but
> >> I thought the comment above that would help a bit:
> >>
> >> /*
> >>           * Peripheral flush must be updated whenever flushing SDP packets is
> >> needed.
> >>           * SDP packets are required for any YUV format (YUV420, YUV422, YUV444).
> >>           */
> >>
> >> The only other way I can think of is maybe we need to introduce a new
> >> phys variable called phys_enc->needs_update_periph_flush and we can set
> >> that in dpu_encoder.c as that can call msm_dp_needs_periph_flush().
> >>
> >> What do you think of this way?
> >
> > Let me understand first the requirements for peripheral flush (see the
> > questions above).
> >
> >>
> >>>>
> >>>>>>>
> >>>>>>> Also, I'd say, we should move update_pending_flush_periph invocation
> >>>>>>> to this patch.
> >>>>>> Ack
> >>>>>>>
> >>>>>>>>        skip_flush:
> >>>>>>>> diff --git a/drivers/gpu/drm/msm/dp/dp_display.c
> >>>>>>>> b/drivers/gpu/drm/msm/dp/dp_display.c
> >>>>>>>> index 6d764f5b08727..4329435518351 100644
> >>>>>>>> --- a/drivers/gpu/drm/msm/dp/dp_display.c
> >>>>>>>> +++ b/drivers/gpu/drm/msm/dp/dp_display.c
> >>>>>>>> @@ -1399,6 +1399,18 @@ void __exit msm_dp_unregister(void)
> >>>>>>>>          platform_driver_unregister(&dp_display_driver);
> >>>>>>>>      }
> >>>>>>>>      +bool msm_dp_is_yuv_420_enabled(const struct msm_dp *dp_display,
> >>>>>>>> +                   const struct drm_display_mode *mode)
> >>>>>>>> +{
> >>>>>>>> +    struct dp_display_private *dp;
> >>>>>>>> +    const struct drm_display_info *info;
> >>>>>>>> +
> >>>>>>>> +    dp = container_of(dp_display, struct dp_display_private,
> >>>>>>>> dp_display);
> >>>>>>>> +    info = &dp_display->connector->display_info;
> >>>>>>>> +
> >>>>>>>> +    return dp_panel_vsc_sdp_supported(dp->panel) &&
> >>>>>>>> drm_mode_is_420_only(info, mode);
> >>>>>>>
> >>>>>>> YUV 420 modes should be filtered out in mode_valid if VSC SDP is not
> >>>>>>> supported.
> >>>>>> Ack. Will change
> >>>>>>>
> >>>>>>>> +}
> >>>>>>>> +
> >>>>>>>>      bool msm_dp_wide_bus_available(const struct msm_dp *dp_display)
> >>>>>>>>      {
> >>>>>>>>          struct dp_display_private *dp;
> >>>>>>>> diff --git a/drivers/gpu/drm/msm/msm_drv.h
> >>>>>>>> b/drivers/gpu/drm/msm/msm_drv.h
> >>>>>>>> index 16a7cbc0b7dd8..b9581bd934e9e 100644
> >>>>>>>> --- a/drivers/gpu/drm/msm/msm_drv.h
> >>>>>>>> +++ b/drivers/gpu/drm/msm/msm_drv.h
> >>>>>>>> @@ -387,7 +387,8 @@ void __exit msm_dp_unregister(void);
> >>>>>>>>      int msm_dp_modeset_init(struct msm_dp *dp_display, struct
> >>>>>>>> drm_device *dev,
> >>>>>>>>                   struct drm_encoder *encoder);
> >>>>>>>>      void msm_dp_snapshot(struct msm_disp_state *disp_state, struct
> >>>>>>>> msm_dp *dp_display);
> >>>>>>>> -
> >>>>>>>> +bool msm_dp_is_yuv_420_enabled(const struct msm_dp *dp_display,
> >>>>>>>> +                   const struct drm_display_mode *mode);
> >>>>>>>>      bool msm_dp_wide_bus_available(const struct msm_dp *dp_display);
> >>>>>>>>        #else
> >>>>>>>> @@ -409,6 +410,12 @@ static inline void msm_dp_snapshot(struct
> >>>>>>>> msm_disp_state *disp_state, struct msm
> >>>>>>>>      {
> >>>>>>>>      }
> >>>>>>>>      +static inline bool msm_dp_is_yuv_420_enabled(const struct msm_dp
> >>>>>>>> *dp_display,
> >>>>>>>> +                         const struct drm_display_mode *mode)
> >>>>>>>> +{
> >>>>>>>> +    return false;
> >>>>>>>> +}
> >>>>>>>> +
> >>>>>>>>      static inline bool msm_dp_wide_bus_available(const struct msm_dp
> >>>>>>>> *dp_display)
> >>>>>>>>      {
> >>>>>>>>          return false;
> >>>>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>> --
> >>>>> With best wishes
> >>>>> Dmitry
> >>>
> >>>
> >>>
> >
> >
> >



--
With best wishes
Dmitry


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