diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 65ff21ae0c271..46d88ef4f59ac 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -733,6 +733,8 @@ EXPORT_SYMBOL(drm_dp_set_subconnector_property); * @dpcd: A cached copy of the connector's DPCD RX capabilities * @desc: A cached copy of the connector's DP descriptor * + * See also: drm_dp_read_sink_count() + * * Returns: %True if the (e)DP connector has a valid sink count that should * be probed, %false otherwise. */ @@ -748,6 +750,30 @@ bool drm_dp_read_sink_count_cap(struct drm_connector *connector, } EXPORT_SYMBOL(drm_dp_read_sink_count_cap); +/** + * drm_dp_read_sink_count() - Retrieve the sink count for a given sink + * @aux: The DP AUX channel to use + * + * See also: drm_dp_read_sink_count_cap() + * + * Returns: The current sink count reported by @aux, or a negative error code + * otherwise. + */ +int drm_dp_read_sink_count(struct drm_dp_aux *aux) +{ + u8 count; + int ret; + + ret = drm_dp_dpcd_readb(aux, DP_SINK_COUNT, &count); + if (ret < 0) + return ret; + if (ret != 1) + return -EIO; + + return DP_GET_SINK_COUNT(count); +} +EXPORT_SYMBOL(drm_dp_read_sink_count); + /* * I2C-over-AUX implementation */ diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 38318ae935f88..0de94fc6289be 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -4648,6 +4648,8 @@ intel_dp_has_sink_count(struct intel_dp *intel_dp) static bool intel_dp_get_dpcd(struct intel_dp *intel_dp) { + int ret; + if (!intel_dp_read_dpcd(intel_dp)) return false; @@ -4664,11 +4666,8 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp) } if (intel_dp_has_sink_count(intel_dp)) { - u8 count; - ssize_t r; - - r = drm_dp_dpcd_readb(&intel_dp->aux, DP_SINK_COUNT, &count); - if (r < 1) + ret = drm_dp_read_sink_count(&intel_dp->aux); + if (ret < 0) return false; /* @@ -4676,7 +4675,7 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp) * a member variable in intel_dp will track any changes * between short pulse interrupts. */ - intel_dp->sink_count = DP_GET_SINK_COUNT(count); + intel_dp->sink_count = ret; /* * SINK_COUNT == 0 and DOWNSTREAM_PORT_PRESENT == 1 implies that diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index 4c56ce4dc54fc..bc5cb8c503fbc 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -1635,6 +1635,7 @@ struct drm_dp_desc; bool drm_dp_read_sink_count_cap(struct drm_connector *connector, const u8 dpcd[DP_RECEIVER_CAP_SIZE], const struct drm_dp_desc *desc); +int drm_dp_read_sink_count(struct drm_dp_aux *aux); void drm_dp_remote_aux_init(struct drm_dp_aux *aux); void drm_dp_aux_init(struct drm_dp_aux *aux);