[PATCH v2] drm/i915/dsc: Change rc parameters calculation for DSC 1.1

[William Tseng]

When calculating dsc parameters, the rc parameters calculated by
calculate_rc_params() is incorrect in the case of DSC 1.1 and
DISPLAY_VER(dev_priv) >= 13. It turns out to be some noise-like
lines are displayed on a MIPI DSI panel supporting DSC 1.1.

The function calculate_rc_params() is implemented by following
the Table E-2 in DSC 1.2a and creates incorrect rc parameters
for DSC 1.1. As a result, add the additional condition
(vdsc_cfg->dsc_version_minor >= 2) to get the right function to
calculate rc parameters for DSC 1.1.

v1: initial version.
v2: modify the commit comment and change the condition
    regarding DSC version checking.

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..b0a7a2179844 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
 	 */
-	if (DISPLAY_VER(dev_priv) >= 13) {
+	if (DISPLAY_VER(dev_priv) >= 13 && vdsc_cfg->dsc_version_minor >= 2) {
 		calculate_rc_params(vdsc_cfg);
 	} else {
 		if ((compressed_bpp == 8 ||
-- 
2.34.1