[Intel-gfx] [PATCH 4/4] drm/i915/dp: Ignore max_requested_bpc if its too low for DSC

[Ankit Nautiyal]

At the moment, while choosing the input bpc for DSC, we take into
account the max_requested_bpc property. This creates a problem, if the
max_requested_bpc is lower than the minimum bpc required by source with
DSC.

So consider max_requested_bpc if its within the limits that we can
support with DSC.

Signed-off-by: Ankit Nautiyal <ankit.k.nauti...@intel.com>
---
 drivers/gpu/drm/i915/display/intel_dp.c | 22 ++++++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_dp.c 
b/drivers/gpu/drm/i915/display/intel_dp.c
index abc718f1a878..ea4c42a5705e 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -1578,6 +1578,16 @@ u8 intel_dp_dsc_max_src_input_bpc(struct 
drm_i915_private *i915)
        return 12;
 }
 
+static int
+intel_dp_dsc_limit_max_bpc(int max_requested_bpc, int src_dsc_max_bpc, int 
src_dsc_min_bpc)
+{
+       /* Consider max_requested_bpc only if src can support it with DSC */
+       if (max_requested_bpc >= src_dsc_min_bpc)
+               return min(src_dsc_max_bpc, max_requested_bpc);
+
+       return src_dsc_max_bpc;
+}
+
 int intel_dp_dsc_compute_max_bpp(const struct intel_connector *connector,
                                 u8 max_req_bpc)
 {
@@ -1591,7 +1601,8 @@ int intel_dp_dsc_compute_max_bpp(const struct 
intel_connector *connector,
        if (!dsc_max_bpc)
                return dsc_max_bpc;
 
-       dsc_max_bpc = min_t(u8, dsc_max_bpc, max_req_bpc);
+       dsc_max_bpc = intel_dp_dsc_limit_max_bpc(max_req_bpc, dsc_max_bpc,
+                                                
intel_dp_dsc_min_src_input_bpc(i915));
 
        num_bpc = drm_dp_dsc_sink_supported_input_bpcs(connector->dp.dsc_dpcd,
                                                       dsc_bpc);
@@ -1959,8 +1970,11 @@ bool is_dsc_pipe_bpp_sufficient(struct drm_i915_private 
*i915,
 {
        u8 dsc_max_bpc, dsc_min_bpc, dsc_max_pipe_bpp, dsc_min_pipe_bpp;
 
-       dsc_max_bpc = min(intel_dp_dsc_max_src_input_bpc(i915), 
conn_state->max_requested_bpc);
        dsc_min_bpc = intel_dp_dsc_min_src_input_bpc(i915);
+       dsc_max_bpc = intel_dp_dsc_max_src_input_bpc(i915);
+
+       dsc_max_bpc = intel_dp_dsc_limit_max_bpc(conn_state->max_requested_bpc,
+                                                dsc_max_bpc, dsc_min_bpc);
 
        dsc_max_pipe_bpp = min(dsc_max_bpc * 3, limits->pipe.max_bpp);
        dsc_min_pipe_bpp = max(dsc_min_bpc * 3, limits->pipe.min_bpp);
@@ -2020,14 +2034,14 @@ static int intel_dp_dsc_compute_pipe_bpp(struct 
intel_dp *intel_dp,
                }
        }
 
+       dsc_min_bpc = intel_dp_dsc_min_src_input_bpc(i915);
        dsc_max_bpc = intel_dp_dsc_max_src_input_bpc(i915);
        if (!dsc_max_bpc)
                return -EINVAL;
 
-       dsc_max_bpc = min_t(u8, dsc_max_bpc, max_req_bpc);
+       dsc_max_bpc = intel_dp_dsc_limit_max_bpc(max_req_bpc, dsc_max_bpc, 
dsc_min_bpc);
        dsc_max_bpp = min(dsc_max_bpc * 3, limits->pipe.max_bpp);
 
-       dsc_min_bpc = intel_dp_dsc_min_src_input_bpc(i915);
        dsc_min_bpp = max(dsc_min_bpc * 3, limits->pipe.min_bpp);
 
        /*
-- 
2.40.1