i915/dp/fec: Cache the FEC_CAPABLE DPCD register (08cadae8) · Commits · 戴 / test

Similar to DSC DPCD registers, let us cache FEC_CAPABLE register to avoid using stale values. With this we can avoid aux reads everytime and instead read the cached values. v2: Avoid using memset and array for a single field. (Manasi,Jani) v3: Print FEC CAPABILITY value. (Manasi) Suggested-by:

Jani Nikula <jani.nikula@linux.intel.com> Cc: Jani Nikula <jani.nikula@linux.intel.com> Cc: Ville Syrjala <ville.syrjala@linux.intel.com> Cc: Manasi Navare <manasi.d.navare@intel.com> Signed-off-by:

Anusha Srivatsa <anusha.srivatsa@intel.com> Reviewed-by:

Manasi Navare <manasi.d.navare@intel.com> Signed-off-by:

Manasi Navare <manasi.d.navare@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181102041455.15818-1-anusha.srivatsa@intel.com

drivers/gpu/drm/i915/intel_dp.c

+12 −0

Original line number	Diff line number	Diff line
		@@ -3954,6 +3954,9 @@ static void intel_dp_get_dsc_sink_cap(struct intel_dp *intel_dp)
		*/
		memset(intel_dp->dsc_dpcd, 0, sizeof(intel_dp->dsc_dpcd));

		/* Clear fec_capable to avoid using stale values */
		intel_dp->fec_capable = 0;

		/* Cache the DSC DPCD if eDP or DP rev >= 1.4 */
		if (intel_dp->dpcd[DP_DPCD_REV] >= 0x14 \|\|
		intel_dp->edp_dpcd[0] >= DP_EDP_14) {
		@@ -3966,6 +3969,15 @@ static void intel_dp_get_dsc_sink_cap(struct intel_dp *intel_dp)
		DRM_DEBUG_KMS("DSC DPCD: %*ph\n",
		(int)sizeof(intel_dp->dsc_dpcd),
		intel_dp->dsc_dpcd);
		/* FEC is supported only on DP 1.4 */
		if (!intel_dp_is_edp(intel_dp)) {
		if (drm_dp_dpcd_readb(&intel_dp->aux, DP_FEC_CAPABILITY,
		&intel_dp->fec_capable) < 0)
		DRM_ERROR("Failed to read FEC DPCD register\n");

		DRM_DEBUG_KMS("FEC CAPABILITY: %x\n",
		intel_dp->fec_capable);
		}
		}
		}

drivers/gpu/drm/i915/intel_drv.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -1114,6 +1114,7 @@ struct intel_dp {
		uint8_t downstream_ports[DP_MAX_DOWNSTREAM_PORTS];
		uint8_t edp_dpcd[EDP_DISPLAY_CTL_CAP_SIZE];
		u8 dsc_dpcd[DP_DSC_RECEIVER_CAP_SIZE];
		u8 fec_capable;
		/* source rates */
		int num_source_rates;
		const int *source_rates;

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