From 89b92339c1362ee910b0c73c2db32af11246c250 Mon Sep 17 00:00:00 2001 From: Mario Kleiner Date: Mon, 5 May 2014 23:03:18 +0200 Subject: [PATCH] drm/radeon: Limit hdmi deep color bit depth to 12 bpc. DCE-4/5/6 can't support more than 12 bpc deep color over hdmi, so clamp to 12 bpc when a hdmi deep color capable display is connected. This even makes sense on DCE-8+, which could do up to 16 bpc, as driving with more than 12 bpc would only waste video bandwidth as long as we don't support framebuffers with more than 12 bpc depth. On pre-DCE4 we clamp hdmi bit depth to 8 bpc, as those asics don't support hdmi deep color. Signed-off-by: Mario Kleiner Signed-off-by: Alex Deucher --- drivers/gpu/drm/radeon/radeon_connectors.c | 25 ++++++++++++++++++++++ 1 file changed, 25 insertions(+) diff --git a/drivers/gpu/drm/radeon/radeon_connectors.c b/drivers/gpu/drm/radeon/radeon_connectors.c index bf73a04791ed..0dc61dde4c3e 100644 --- a/drivers/gpu/drm/radeon/radeon_connectors.c +++ b/drivers/gpu/drm/radeon/radeon_connectors.c @@ -145,6 +145,31 @@ int radeon_get_monitor_bpc(struct drm_connector *connector) } break; } + + if (drm_detect_hdmi_monitor(radeon_connector->edid)) { + /* hdmi deep color only implemented on DCE4+ */ + if ((bpc > 8) && !ASIC_IS_DCE4(rdev)) { + DRM_DEBUG("%s: HDMI deep color %d bpc unsupported. Using 8 bpc.\n", + drm_get_connector_name(connector), bpc); + bpc = 8; + } + + /* + * Pre DCE-8 hw can't handle > 12 bpc, and more than 12 bpc doesn't make + * much sense without support for > 12 bpc framebuffers. RGB 4:4:4 at + * 12 bpc is always supported on hdmi deep color sinks, as this is + * required by the HDMI-1.3 spec. Clamp to a safe 12 bpc maximum. + */ + if (bpc > 12) { + DRM_DEBUG("%s: HDMI deep color %d bpc unsupported. Using 12 bpc.\n", + drm_get_connector_name(connector), bpc); + bpc = 12; + } + } + + DRM_DEBUG("%s: Display bpc=%d, returned bpc=%d\n", + drm_get_connector_name(connector), connector->display_info.bpc, bpc); + return bpc; } -- 2.34.1