On 9/26/2024 2:46 PM, Jani Nikula wrote:
On Wed, 13 Dec 2023, Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx> wrote:
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.nautiyal@xxxxxxxxx>
---
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 e8aa2f469142..0014aa5ea652 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -1638,6 +1638,16 @@ int 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)
{
@@ -1651,7 +1661,8 @@ int intel_dp_dsc_compute_max_bpp(const struct intel_connector *connector,
if (!dsc_max_bpc)
return dsc_max_bpc;
- dsc_max_bpc = min(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));
Somehow that doesn't read so well.
I think something like this would improve clarity:
dsc_min_bpc = intel_dp_dsc_min_src_input_bpc(i915);
dsc_max_bpc = intel_dp_dsc_max_src_input_bpc(i915);
max_req_bpc = clamp(max_req_bpc, dsc_min_bpc, dsc_max_bpc);
i.e. clamp the request to reasonable limits. That's more like regular
input checking. That should be done *everywhere* when
conn_state->max_requested_bpc is used.
Then min(dsc_max_bpc, max_req_bpc) is no longer needed because
max_req_bpc <= dsc_max_bpc is guaranteed.
IOW this becomes:
dsc_max_bpc = clamp(max_req_bpc, dsc_min_bpc, dsc_max_bpc);
You are right, clamping is the correct thing here.
Also realized that we actually do not need to explicitly check
max_req_bpc, as its already taken into account.
I have sent new rev of the series with the above addressed and some more
refactoring.
Regards,
Ankit
BR,
Jani.
num_bpc = drm_dp_dsc_sink_supported_input_bpcs(connector->dp.dsc_dpcd,
dsc_bpc);
@@ -2039,8 +2050,11 @@ bool is_dsc_pipe_bpp_sufficient(struct drm_i915_private *i915,
{
int 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);
@@ -2100,14 +2114,14 @@ 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(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);
/*
