[PATCH 02/16] drm/i915/display: Prepare for dsc 3 stream splitter

Nautiyal, Ankit K ankit.k.nautiyal at intel.com
Tue Oct 22 04:51:03 UTC 2024


On 10/22/2024 9:23 AM, Nautiyal, Ankit K wrote:
>
> On 10/21/2024 6:16 PM, Jani Nikula wrote:
>> On Mon, 21 Oct 2024, Ankit Nautiyal <ankit.k.nautiyal at intel.com> wrote:
>>> At the moment dsc_split represents that dsc splitter is used or not.
>>> With 3 DSC engines, the splitter can split into two streams or three
>>> streams. Make the member dsc_split as int and set that to 2 when dsc
>>> splitter splits to 2 stream.
>> Maybe also name it accordingly? "dsc split" sounds like a boolean, not
>> like an int.
>>
>> Moreover, when you change the meaning of a member, it's often good code
>> hygiene to rename the member to catch any incorrect uses and to ensure
>> you changed them all.
>
> Noted. Will change the name accordingly.
>
>>
>>> v2: Avoid new enum for dsc split. (Suraj)
>>>
>>> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
>>> ---
>>>   drivers/gpu/drm/i915/display/icl_dsi.c        |  2 +-
>>>   drivers/gpu/drm/i915/display/intel_display.c  |  2 +-
>>>   .../drm/i915/display/intel_display_types.h    |  2 +-
>>>   drivers/gpu/drm/i915/display/intel_dp.c       |  2 +-
>>>   drivers/gpu/drm/i915/display/intel_vdsc.c     | 20 
>>> ++++++++++++++-----
>>>   5 files changed, 19 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/display/icl_dsi.c 
>>> b/drivers/gpu/drm/i915/display/icl_dsi.c
>>> index 87a27d91d15d..553e75cf118c 100644
>>> --- a/drivers/gpu/drm/i915/display/icl_dsi.c
>>> +++ b/drivers/gpu/drm/i915/display/icl_dsi.c
>>> @@ -1595,7 +1595,7 @@ static int gen11_dsi_dsc_compute_config(struct 
>>> intel_encoder *encoder,
>>>         /* FIXME: split only when necessary */
>>>       if (crtc_state->dsc.slice_count > 1)
>>> -        crtc_state->dsc.dsc_split = true;
>>> +        crtc_state->dsc.dsc_split = 2;
>>>         /* FIXME: initialize from VBT */
>>>       vdsc_cfg->rc_model_size = DSC_RC_MODEL_SIZE_CONST;
>>> diff --git a/drivers/gpu/drm/i915/display/intel_display.c 
>>> b/drivers/gpu/drm/i915/display/intel_display.c
>>> index ef1436146325..9e2f0fd0558f 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_display.c
>>> +++ b/drivers/gpu/drm/i915/display/intel_display.c
>>> @@ -5741,7 +5741,7 @@ intel_pipe_config_compare(const struct 
>>> intel_crtc_state *current_config,
>>>       PIPE_CONF_CHECK_I(dsc.config.nsl_bpg_offset);
>>>         PIPE_CONF_CHECK_BOOL(dsc.compression_enable);
>>> -    PIPE_CONF_CHECK_BOOL(dsc.dsc_split);
>>> +    PIPE_CONF_CHECK_I(dsc.dsc_split);
>>>       PIPE_CONF_CHECK_I(dsc.compressed_bpp_x16);
>>>         PIPE_CONF_CHECK_BOOL(splitter.enable);
>>> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h 
>>> b/drivers/gpu/drm/i915/display/intel_display_types.h
>>> index 2bb1fa64da2f..58f510909f4d 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
>>> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
>>> @@ -1235,7 +1235,7 @@ struct intel_crtc_state {
>>>       /* Display Stream compression state */
>>>       struct {
>>>           bool compression_enable;
>>> -        bool dsc_split;
>>> +        int dsc_split;
>>>           /* Compressed Bpp in U6.4 format (first 4 bits for 
>>> fractional part) */
>>>           u16 compressed_bpp_x16;
>>>           u8 slice_count;
>>> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c 
>>> b/drivers/gpu/drm/i915/display/intel_dp.c
>>> index 286b272aa98c..c1867c883b73 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_dp.c
>>> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
>>> @@ -2409,7 +2409,7 @@ int intel_dp_dsc_compute_config(struct 
>>> intel_dp *intel_dp,
>>>        * then we need to use 2 VDSC instances.
>>>        */
>>>       if (pipe_config->joiner_pipes || pipe_config->dsc.slice_count 
>>> > 1)
>>> -        pipe_config->dsc.dsc_split = true;
>>> +        pipe_config->dsc.dsc_split = 2;
>>>         ret = intel_dp_dsc_compute_params(connector, pipe_config);
>>>       if (ret < 0) {
>>> diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.c 
>>> b/drivers/gpu/drm/i915/display/intel_vdsc.c
>>> index 40525f5c4c42..3bce13c21756 100644
>>> --- a/drivers/gpu/drm/i915/display/intel_vdsc.c
>>> +++ b/drivers/gpu/drm/i915/display/intel_vdsc.c
>>> @@ -379,7 +379,14 @@ intel_dsc_power_domain(struct intel_crtc *crtc, 
>>> enum transcoder cpu_transcoder)
>>>     static int intel_dsc_get_vdsc_per_pipe(const struct 
>>> intel_crtc_state *crtc_state)
>>>   {
>>> -    return crtc_state->dsc.dsc_split ? 2 : 1;
>>> +    switch (crtc_state->dsc.dsc_split) {
>>> +    case 2:
>>> +        return 2;
>>> +    case 0:
>>> +    default:
>>> +        break;
>>> +    }
>>> +    return 1;
>> Seems overly complicated.
>>
>>>   }
>>>     int intel_dsc_get_num_vdsc_instances(const struct 
>>> intel_crtc_state *crtc_state)
>>> @@ -976,8 +983,11 @@ void intel_dsc_get_config(struct 
>>> intel_crtc_state *crtc_state)
>>>       if (!crtc_state->dsc.compression_enable)
>>>           goto out;
>>>   -    crtc_state->dsc.dsc_split = (dss_ctl2 & 
>>> RIGHT_BRANCH_VDSC_ENABLE) &&
>>> -        (dss_ctl1 & JOINER_ENABLE);
>>> +    if ((dss_ctl1 & JOINER_ENABLE) &&
>>> +        (dss_ctl2 & RIGHT_BRANCH_VDSC_ENABLE))
>> The extra parens are unnecessary.
>>
>>> +        crtc_state->dsc.dsc_split = 2;
>>> +    else
>>> +        crtc_state->dsc.dsc_split = 0;
>>>         intel_dsc_get_pps_config(crtc_state);
>>>   out:
>>> @@ -988,10 +998,10 @@ static void intel_vdsc_dump_state(struct 
>>> drm_printer *p, int indent,
>>>                     const struct intel_crtc_state *crtc_state)
>>>   {
>>>       drm_printf_indent(p, indent,
>>> -              "dsc-dss: compressed-bpp:" FXP_Q4_FMT ", slice-count: 
>>> %d, split: %s\n",
>>> +              "dsc-dss: compressed-bpp:" FXP_Q4_FMT ", slice-count: 
>>> %d, split: %d\n",
>> So what does the reader think when they see "split: 1" in the logs?
>> Split enabled?
>
> I was meaning to capture the DSC split state as originally intended, 
> and extend it to have splitting to 3, 2, or None.
>
> With that we can never have split: 1, but can have either 3, 2, or 0.
>
> I realize, split:0 is a bit ambiguous, so I am thinking about:
>
> -change the dsc_split to dsc_streams: to capture number of DSC streams 
> per pipe, instead of DSC splitter operation.
>
> -dsc_streams can be 1, 2 and extended to 3.
>
> -Splitter state will then be implicit, 1 DSC Stream => No Splitter, 2 
> DSC Streams => Splitter used to split 2 DSC streams and so on.
>
> With that, deriving number of DSC engine will also be straight forward 
> (avoiding the switch case above).

Suraj,

You were actually pointing to the same thing in last version, sorry to 
misunderstand you. I did remove the complicated enum but some how missed 
this.

Will change this as you had originally suggested.

Thanks & Regards,

Ankit

>
>
> Thanks & Regards,
>
> Ankit
>
>
>
>>
>>> FXP_Q4_ARGS(crtc_state->dsc.compressed_bpp_x16),
>>>                 crtc_state->dsc.slice_count,
>>> -              str_yes_no(crtc_state->dsc.dsc_split));
>>> +              crtc_state->dsc.dsc_split);
>>>   }
>>>     void intel_vdsc_state_dump(struct drm_printer *p, int indent,


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