Commit c7669520 authored by Suraj Kandpal's avatar Suraj Kandpal
Browse files

drm/i915/dp: Add a meaningful return to intel_dp_read_dsc_dpcd 



Add a meaningful return to intel_dp_read_dsc_dpcd. This is to avoid
unwanted DPCD reads which are not needed once we know DSC DPCD
read fails. To do this convert drm_dp_dpcd_read to drm_dp_dpcd_read_data
which returns a meaningful error which can be propogated up when all
bits are not read.
While we are at it convert the drm_err in intel_dp_read_dsc_dpcd to
drm_dbg_kms. This is because we do not want a hard ERROR when we
call this function, during the intel_dp_detect phase since AUX may not
be up, it is expected to fail but we do not expect a failure in read
when we call intel_dp_dsc_get_sink_cap so we move the drm_err there.

Signed-off-by: default avatarSuraj Kandpal <suraj.kandpal@intel.com>
Reviewed-by: default avatarAnkit Nautiyal <ankit.k.nautiyal@intel.com>
Link: https://patch.msgid.link/20260202081801.1400708-1-suraj.kandpal@intel.com
parent c0dc68f4

drivers/gpu/drm/i915/display/intel_dp.c

+19 −12
Original line number Diff line number Diff line
@@ -4281,20 +4281,24 @@ static bool intel_dp_get_colorimetry_status(struct intel_dp *intel_dp) 
	return dprx & DP_VSC_SDP_EXT_FOR_COLORIMETRY_SUPPORTED;

}



static void intel_dp_read_dsc_dpcd(struct drm_dp_aux *aux,

static int intel_dp_read_dsc_dpcd(struct drm_dp_aux *aux,

				  u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE])

{

	if (drm_dp_dpcd_read(aux, DP_DSC_SUPPORT, dsc_dpcd,

			     DP_DSC_RECEIVER_CAP_SIZE) < 0) {

		drm_err(aux->drm_dev,

			"Failed to read DPCD register 0x%x\n",

			DP_DSC_SUPPORT);

		return;

	int ret;



	ret = drm_dp_dpcd_read_data(aux, DP_DSC_SUPPORT, dsc_dpcd,

				    DP_DSC_RECEIVER_CAP_SIZE);

	if (ret) {

		drm_dbg_kms(aux->drm_dev,

			    "Could not read DSC DPCD register 0x%x Error: %pe\n",

			    DP_DSC_SUPPORT, ERR_PTR(ret));

		return ret;

	}



	drm_dbg_kms(aux->drm_dev, "DSC DPCD: %*ph\n",

		    DP_DSC_RECEIVER_CAP_SIZE,

		    dsc_dpcd);

	return 0;

}



static void init_dsc_overall_throughput_limits(struct intel_connector *connector, bool is_branch)
@@ -4345,8 +4349,9 @@ void intel_dp_get_dsc_sink_cap(u8 dpcd_rev, 
	if (dpcd_rev < DP_DPCD_REV_14)

		return;



	intel_dp_read_dsc_dpcd(connector->dp.dsc_decompression_aux,

			       connector->dp.dsc_dpcd);

	if (intel_dp_read_dsc_dpcd(connector->dp.dsc_decompression_aux,

				   connector->dp.dsc_dpcd) < 0)

		return;



	if (drm_dp_dpcd_readb(connector->dp.dsc_decompression_aux, DP_FEC_CAPABILITY,

			      &connector->dp.fec_capability) < 0) {
@@ -4376,7 +4381,9 @@ static void intel_edp_get_dsc_sink_cap(u8 edp_dpcd_rev, struct intel_connector * 
	if (edp_dpcd_rev < DP_EDP_14)

		return;



	intel_dp_read_dsc_dpcd(connector->dp.dsc_decompression_aux, connector->dp.dsc_dpcd);

	if (intel_dp_read_dsc_dpcd(connector->dp.dsc_decompression_aux,

				   connector->dp.dsc_dpcd) < 0)

		return;



	if (connector->dp.dsc_dpcd[0] & DP_DSC_DECOMPRESSION_IS_SUPPORTED)

		init_dsc_overall_throughput_limits(connector, false);