On Tue, 22 Oct 2024, "Nautiyal, Ankit K" <ankit.k.nautiyal@xxxxxxxxx> wrote:
> On 10/21/2024 6:16 PM, Jani Nikula wrote:
>> On Mon, 21 Oct 2024, Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx> 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@xxxxxxxxx>
>>> ---
>>> 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).
Maybe be even more explicit, and call it num_streams or stream_count or
something like that.
Also, the crtc_state->dsc.dsc_something is a tautology, the dsc_ prefix
is unnecessary when it's already in a dsc substruct.
BR,
Jani.
>
>
> 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,
--
Jani Nikula, Intel
