diff mbox series

[02/14] drm/i915/dp: Add intel_dp_dsc_bpp_step_x16() helper to get DSC BPP precision

Message ID ed109ed88a6ae3849871ec341cb5ab2088097dd3.1738327620.git.jani.nikula@intel.com (mailing list archive)
State New
Headers show
Series drm/i915/dp: dsc fix, refactoring and cleanups | expand

Commit Message

Jani Nikula Jan. 31, 2025, 12:49 p.m. UTC
Add a platform independent helper for getting the supported DSC BPP step
for the link.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

Comments

Imre Deak Jan. 31, 2025, 1:45 p.m. UTC | #1
On Fri, Jan 31, 2025 at 02:49:55PM +0200, Jani Nikula wrote:
> Add a platform independent helper for getting the supported DSC BPP step
> for the link.
> 
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp.c | 21 ++++++++++++++++-----
>  1 file changed, 16 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> index ecf192262eb9..a7a5bb2075da 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -2054,6 +2054,21 @@ static int dsc_src_max_compressed_bpp(struct intel_dp *intel_dp)
>  		return 27;
>  }
>  
> +/*
> + * Note: for pre-13 display you still need to check the validity of each step.
> + */
> +static int intel_dp_dsc_bpp_step_x16(const struct intel_connector *connector)

Nit: there was a guideline that these KMS objects should be passed around via
non-const pointers vs. state pointers which should be const if possible.

> +{
> +	struct intel_display *display = to_intel_display(connector);
> +	u8 incr = drm_dp_dsc_sink_bpp_incr(connector->dp.dsc_dpcd);
> +
> +	if (DISPLAY_VER(display) < 14 || !incr)
> +		return fxp_q4_from_int(1);
> +
> +	/* fxp q4 */
> +	return 16 / incr;

Nit: could've been fxp_q4_from_int(1) / incr;

Regardless of the nits, patch looks ok:

Reviewed-by: Imre Deak <imre.deak@intel.com>

> +}
> +
>  /*
>   * From a list of valid compressed bpps try different compressed bpp and find a
>   * suitable link configuration that can support it.
> @@ -2110,16 +2125,12 @@ xelpd_dsc_compute_link_config(struct intel_dp *intel_dp,
>  			      int timeslots)
>  {
>  	struct intel_display *display = to_intel_display(intel_dp);
> -	u8 bppx16_incr = drm_dp_dsc_sink_bpp_incr(connector->dp.dsc_dpcd);
>  	int output_bpp = intel_dp_output_bpp(pipe_config->output_format, pipe_bpp);
>  	u16 compressed_bppx16;
>  	u8 bppx16_step;
>  	int ret;
>  
> -	if (DISPLAY_VER(display) < 14 || bppx16_incr <= 1)
> -		bppx16_step = 16;
> -	else
> -		bppx16_step = 16 / bppx16_incr;
> +	bppx16_step = intel_dp_dsc_bpp_step_x16(connector);
>  
>  	/* Compressed BPP should be less than the Input DSC bpp */
>  	dsc_max_bpp = min(dsc_max_bpp << 4, (output_bpp << 4) - bppx16_step);
> -- 
> 2.39.5
>
Jani Nikula Jan. 31, 2025, 2:06 p.m. UTC | #2
On Fri, 31 Jan 2025, Imre Deak <imre.deak@intel.com> wrote:
> On Fri, Jan 31, 2025 at 02:49:55PM +0200, Jani Nikula wrote:
>> Add a platform independent helper for getting the supported DSC BPP step
>> for the link.
>> 
>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>> ---
>>  drivers/gpu/drm/i915/display/intel_dp.c | 21 ++++++++++++++++-----
>>  1 file changed, 16 insertions(+), 5 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
>> index ecf192262eb9..a7a5bb2075da 100644
>> --- a/drivers/gpu/drm/i915/display/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
>> @@ -2054,6 +2054,21 @@ static int dsc_src_max_compressed_bpp(struct intel_dp *intel_dp)
>>  		return 27;
>>  }
>>  
>> +/*
>> + * Note: for pre-13 display you still need to check the validity of each step.
>> + */
>> +static int intel_dp_dsc_bpp_step_x16(const struct intel_connector *connector)
>
> Nit: there was a guideline that these KMS objects should be passed around via
> non-const pointers vs. state pointers which should be const if possible.

At this point, xelpd_dsc_compute_link_config() only has the const
variable available. This changes later in the series.

>
>> +{
>> +	struct intel_display *display = to_intel_display(connector);
>> +	u8 incr = drm_dp_dsc_sink_bpp_incr(connector->dp.dsc_dpcd);
>> +
>> +	if (DISPLAY_VER(display) < 14 || !incr)
>> +		return fxp_q4_from_int(1);
>> +
>> +	/* fxp q4 */
>> +	return 16 / incr;
>
> Nit: could've been fxp_q4_from_int(1) / incr;

Good point, will fix.

>
> Regardless of the nits, patch looks ok:
>
> Reviewed-by: Imre Deak <imre.deak@intel.com>

Thanks!

>
>> +}
>> +
>>  /*
>>   * From a list of valid compressed bpps try different compressed bpp and find a
>>   * suitable link configuration that can support it.
>> @@ -2110,16 +2125,12 @@ xelpd_dsc_compute_link_config(struct intel_dp *intel_dp,
>>  			      int timeslots)
>>  {
>>  	struct intel_display *display = to_intel_display(intel_dp);
>> -	u8 bppx16_incr = drm_dp_dsc_sink_bpp_incr(connector->dp.dsc_dpcd);
>>  	int output_bpp = intel_dp_output_bpp(pipe_config->output_format, pipe_bpp);
>>  	u16 compressed_bppx16;
>>  	u8 bppx16_step;
>>  	int ret;
>>  
>> -	if (DISPLAY_VER(display) < 14 || bppx16_incr <= 1)
>> -		bppx16_step = 16;
>> -	else
>> -		bppx16_step = 16 / bppx16_incr;
>> +	bppx16_step = intel_dp_dsc_bpp_step_x16(connector);
>>  
>>  	/* Compressed BPP should be less than the Input DSC bpp */
>>  	dsc_max_bpp = min(dsc_max_bpp << 4, (output_bpp << 4) - bppx16_step);
>> -- 
>> 2.39.5
>>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index ecf192262eb9..a7a5bb2075da 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -2054,6 +2054,21 @@  static int dsc_src_max_compressed_bpp(struct intel_dp *intel_dp)
 		return 27;
 }
 
+/*
+ * Note: for pre-13 display you still need to check the validity of each step.
+ */
+static int intel_dp_dsc_bpp_step_x16(const struct intel_connector *connector)
+{
+	struct intel_display *display = to_intel_display(connector);
+	u8 incr = drm_dp_dsc_sink_bpp_incr(connector->dp.dsc_dpcd);
+
+	if (DISPLAY_VER(display) < 14 || !incr)
+		return fxp_q4_from_int(1);
+
+	/* fxp q4 */
+	return 16 / incr;
+}
+
 /*
  * From a list of valid compressed bpps try different compressed bpp and find a
  * suitable link configuration that can support it.
@@ -2110,16 +2125,12 @@  xelpd_dsc_compute_link_config(struct intel_dp *intel_dp,
 			      int timeslots)
 {
 	struct intel_display *display = to_intel_display(intel_dp);
-	u8 bppx16_incr = drm_dp_dsc_sink_bpp_incr(connector->dp.dsc_dpcd);
 	int output_bpp = intel_dp_output_bpp(pipe_config->output_format, pipe_bpp);
 	u16 compressed_bppx16;
 	u8 bppx16_step;
 	int ret;
 
-	if (DISPLAY_VER(display) < 14 || bppx16_incr <= 1)
-		bppx16_step = 16;
-	else
-		bppx16_step = 16 / bppx16_incr;
+	bppx16_step = intel_dp_dsc_bpp_step_x16(connector);
 
 	/* Compressed BPP should be less than the Input DSC bpp */
 	dsc_max_bpp = min(dsc_max_bpp << 4, (output_bpp << 4) - bppx16_step);