drm/i915/dp: Avoid forcing DSC BPC for MST case

For MST the bpc is hardcoded to 8, and pipe bpp to 24.
So avoid forcing DSC bpc for MST case.

v2: Warn and ignore the debug flag than to bail out. (Jani)

v3: Fix dbg message to mention forced bpc instead of bpp.

v4: Fix checkpatch longline warning.

Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230817142459.89764-9-ankit.k.nautiyal@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index 0b85af7316f46f60e5f7ae631442a9f0d982cbc5..d6fd453ade6b017d1a0c2c2ccd8ae2b8f266cf06 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -1697,14 +1697,14 @@ int intel_dp_dsc_compute_config(struct intel_dp *intel_dp,
        if (!intel_dp_dsc_supports_format(intel_dp, pipe_config->output_format))
                return -EINVAL;
 
-       if (compute_pipe_bpp)
+       if (intel_dp->force_dsc_bpc && compute_pipe_bpp) {
+               pipe_bpp = intel_dp->force_dsc_bpc * 3;
+               drm_dbg_kms(&dev_priv->drm, "Input DSC BPC forced to %d\n",
+                           intel_dp->force_dsc_bpc);
+       } else if (compute_pipe_bpp) {
                pipe_bpp = intel_dp_dsc_compute_bpp(intel_dp, conn_state->max_requested_bpc);
-       else
+       } else {
                pipe_bpp = pipe_config->pipe_bpp;
-
-       if (intel_dp->force_dsc_bpc) {
-               pipe_bpp = intel_dp->force_dsc_bpc * 3;
-               drm_dbg_kms(&dev_priv->drm, "Input DSC BPP forced to %d", pipe_bpp);
        }
 
        /* Min Input BPC for ICL+ is 8 */

diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
index 1f00713fb1ad11f1bf02ef37feac35238edffac9..dff4717edbd063dfa89f981144b305badbab7a2e 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
@@ -361,6 +361,11 @@ static int intel_dp_mst_compute_config(struct intel_encoder *encoder,
        /* enable compression if the mode doesn't fit available BW */
        drm_dbg_kms(&dev_priv->drm, "Force DSC en = %d\n", intel_dp->force_dsc_en);
        if (ret || intel_dp->force_dsc_en) {
+               /*
+                * FIXME: As bpc is hardcoded to 8, as mentioned above,
+                * WARN and ignore the debug flag force_dsc_bpc for now.
+                */
+               drm_WARN(&dev_priv->drm, intel_dp->force_dsc_bpc, "Cannot Force BPC for MST\n");
                /*
                 * Try to get at least some timeslots and then see, if
                 * we can fit there with DSC.