[PATCH] drm/i915/dsc: Change rc parameters calculation for DSC 1.1

[Kandpal, Suraj]

> -----Original Message-----
> From: Tseng, William <william.tseng at intel.com>
> Sent: Thursday, February 20, 2025 8:56 AM
> To: intel-gfx at lists.freedesktop.org
> Cc: Tseng, William <william.tseng at intel.com>; Kandpal, Suraj
> <suraj.kandpal at intel.com>; Heikkila, Juha-pekka <juha-
> pekka.heikkila at intel.com>
> Subject: [PATCH] drm/i915/dsc: Change rc parameters calculation for DSC 1.1
> 


So to start with this needs to be sent intel-xe mailing list too

> When calculating dsc parameters, the rc parameters calculated by
> calculate_rc_params() may be incorrect in the case of DSC 1.1 and

"Maybe" does not work to get the patch merged we need specifically
what param does not work in calculate rc params so needs some more debug
before sending a patch over.
You can compare the dsc param dump when we use calculate rc params vs when we
Use the tables

> DISPLAY_VER(dev_priv) >= 13 and cause noise-like lines displayed on a MIPI DSI
> panel supporting DSC 1.1. The calculation seems for DSC 1.2 only. So, instead of
> calculate_rc_params(), calculate the rc paramerters with the function
> drm_dsc_setup_rc_params() for DSC 1.1.
> 
> Cc: Suraj Kandpal <suraj.kandpal at intel.com>
> Cc: Juha-Pekka Heikkil <juha-pekka.heikkila at intel.com>
> Signed-off-by: William Tseng <william.tseng at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_vdsc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.c
> b/drivers/gpu/drm/i915/display/intel_vdsc.c
> index b355c479eda3..e3443a1d12e0 100644
> --- a/drivers/gpu/drm/i915/display/intel_vdsc.c
> +++ b/drivers/gpu/drm/i915/display/intel_vdsc.c
> @@ -320,7 +320,7 @@ int intel_dsc_compute_params(struct intel_crtc_state
> *pipe_config)
>  	 * upto uncompressed bpp-1, hence add calculations for all the rc
>  	 * parameters
>  	 */

You need to amend to comment explain the additional conditions

> -	if (DISPLAY_VER(dev_priv) >= 13) {
> +	if (DISPLAY_VER(dev_priv) >= 13 && vdsc_cfg->dsc_version_minor ==
> 2) {

Needs to be >= 2

Regards,
Suraj Kandpal

>  		calculate_rc_params(vdsc_cfg);
>  	} else {
>  		if ((compressed_bpp == 8 ||
> --
> 2.34.1