From aa019b791a3e138ca0eaa38e72b4ea97d482a7bc Mon Sep 17 00:00:00 2001 From: Alex Deucher Date: Wed, 30 Apr 2014 09:27:15 -0400 Subject: [PATCH] drm/radeon/dp: check for errors in dpcd reads MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Check to make sure the transaction succeeded before using the register value. Fixes occasional link training problems. Noticed-by: Sergei Antonov Signed-off-by: Alex Deucher Signed-off-by: Christian König --- drivers/gpu/drm/radeon/atombios_dp.c | 44 ++++++++++++++++------------ 1 file changed, 25 insertions(+), 19 deletions(-) diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c index bc0119fb6c12..54e4f52549af 100644 --- a/drivers/gpu/drm/radeon/atombios_dp.c +++ b/drivers/gpu/drm/radeon/atombios_dp.c @@ -366,11 +366,11 @@ static void radeon_dp_probe_oui(struct radeon_connector *radeon_connector) if (!(dig_connector->dpcd[DP_DOWN_STREAM_PORT_COUNT] & DP_OUI_SUPPORT)) return; - if (drm_dp_dpcd_read(&radeon_connector->ddc_bus->aux, DP_SINK_OUI, buf, 3)) + if (drm_dp_dpcd_read(&radeon_connector->ddc_bus->aux, DP_SINK_OUI, buf, 3) == 3) DRM_DEBUG_KMS("Sink OUI: %02hx%02hx%02hx\n", buf[0], buf[1], buf[2]); - if (drm_dp_dpcd_read(&radeon_connector->ddc_bus->aux, DP_BRANCH_OUI, buf, 3)) + if (drm_dp_dpcd_read(&radeon_connector->ddc_bus->aux, DP_BRANCH_OUI, buf, 3) == 3) DRM_DEBUG_KMS("Branch OUI: %02hx%02hx%02hx\n", buf[0], buf[1], buf[2]); } @@ -419,21 +419,23 @@ int radeon_dp_get_panel_mode(struct drm_encoder *encoder, if (dp_bridge != ENCODER_OBJECT_ID_NONE) { /* DP bridge chips */ - drm_dp_dpcd_readb(&radeon_connector->ddc_bus->aux, - DP_EDP_CONFIGURATION_CAP, &tmp); - if (tmp & 1) - panel_mode = DP_PANEL_MODE_INTERNAL_DP2_MODE; - else if ((dp_bridge == ENCODER_OBJECT_ID_NUTMEG) || - (dp_bridge == ENCODER_OBJECT_ID_TRAVIS)) - panel_mode = DP_PANEL_MODE_INTERNAL_DP1_MODE; - else - panel_mode = DP_PANEL_MODE_EXTERNAL_DP_MODE; + if (drm_dp_dpcd_readb(&radeon_connector->ddc_bus->aux, + DP_EDP_CONFIGURATION_CAP, &tmp) == 1) { + if (tmp & 1) + panel_mode = DP_PANEL_MODE_INTERNAL_DP2_MODE; + else if ((dp_bridge == ENCODER_OBJECT_ID_NUTMEG) || + (dp_bridge == ENCODER_OBJECT_ID_TRAVIS)) + panel_mode = DP_PANEL_MODE_INTERNAL_DP1_MODE; + else + panel_mode = DP_PANEL_MODE_EXTERNAL_DP_MODE; + } } else if (connector->connector_type == DRM_MODE_CONNECTOR_eDP) { /* eDP */ - drm_dp_dpcd_readb(&radeon_connector->ddc_bus->aux, - DP_EDP_CONFIGURATION_CAP, &tmp); - if (tmp & 1) - panel_mode = DP_PANEL_MODE_INTERNAL_DP2_MODE; + if (drm_dp_dpcd_readb(&radeon_connector->ddc_bus->aux, + DP_EDP_CONFIGURATION_CAP, &tmp) == 1) { + if (tmp & 1) + panel_mode = DP_PANEL_MODE_INTERNAL_DP2_MODE; + } } return panel_mode; @@ -809,11 +811,15 @@ void radeon_dp_link_train(struct drm_encoder *encoder, else dp_info.enc_id |= ATOM_DP_CONFIG_LINK_A; - drm_dp_dpcd_readb(&radeon_connector->ddc_bus->aux, DP_MAX_LANE_COUNT, &tmp); - if (ASIC_IS_DCE5(rdev) && (tmp & DP_TPS3_SUPPORTED)) - dp_info.tp3_supported = true; - else + if (drm_dp_dpcd_readb(&radeon_connector->ddc_bus->aux, DP_MAX_LANE_COUNT, &tmp) + == 1) { + if (ASIC_IS_DCE5(rdev) && (tmp & DP_TPS3_SUPPORTED)) + dp_info.tp3_supported = true; + else + dp_info.tp3_supported = false; + } else { dp_info.tp3_supported = false; + } memcpy(dp_info.dpcd, dig_connector->dpcd, DP_RECEIVER_CAP_SIZE); dp_info.rdev = rdev; -- 2.30.2