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

Abhinav Kumar quic_abhinavk at quicinc.com
Mon Jan 29 05:03:42 UTC 2024



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.

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().

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.

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?

>>
>>>>>
>>>>> 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
> 
> 
> 


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