drm/radeon: Extended DDC Probing for Connectors with Improperly Wired DDC Lines (here: Asus M2A-VM HDMI)
Some integrated ATI Radeon chipset implementations with add-on HDMI card
(e. g. Asus M2A-VM HDMI) indicate the availability of a DDC even
when the add-on card is not plugged in or HDMI is disabled in BIOS setup.
In this case, drm_get_edid() and drm_edid_block_valid() periodically
dump data and kernel errors into system log files and onto terminals.
For these connectors DDC probing is extended by a check for a correct
EDID header. Only in case a valid EDID header is also found, the
(HDMI or DVI) connector will be used by the Radeon driver. This prevents
the kernel driver from useless flooding of logs and terminal sessions with
EDID dumps and error messages.
This patch adds a flag 'requires_extended_probe' to the radeon_connector
structure. In function radeon_connector_needs_extended_probe() this flag
can be set on a chipset family/vendor/connector type specific basis.
In addition, function radeon_ddc_probe() has been adapted to perform
extended DDC probing if required by the connector's flag.
Requires function drm_edid_header_is_valid() in DRM module provided by
[PATCH] drm: Separate EDID Header Check from EDID Block Check.
Tested for kernel 2.6.35, 2.6.38 and 3.0 on Asus M2A-VM HDMI board
BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=668196
BugLink: http://bugs.launchpad.net/bugs/7228066
Cc: <stable@kernel.org>
Signed-off-by: Thomas Reim <reimth@gmail.com>
Reviewed-by: Alex Deucher <alexdeucher@gmail.com>
Acked-by: Stephen Michaels <Stephen.Micheals@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_mode.h b/drivers/gpu/drm/radeon/radeon_mode.h
index 6df4e3c..d09031c 100644
--- a/drivers/gpu/drm/radeon/radeon_mode.h
+++ b/drivers/gpu/drm/radeon/radeon_mode.h
@@ -438,6 +438,9 @@
struct radeon_i2c_chan *ddc_bus;
/* some systems have an hdmi and vga port with a shared ddc line */
bool shared_ddc;
+ /* for some Radeon chip families we apply an additional EDID header
+ check as part of the DDC probe */
+ bool requires_extended_probe;
bool use_digital;
/* we need to mind the EDID between detect
and get modes due to analog/digital/tvencoder */
@@ -514,7 +517,8 @@
u8 val);
extern void radeon_router_select_ddc_port(struct radeon_connector *radeon_connector);
extern void radeon_router_select_cd_port(struct radeon_connector *radeon_connector);
-extern bool radeon_ddc_probe(struct radeon_connector *radeon_connector);
+extern bool radeon_ddc_probe(struct radeon_connector *radeon_connector,
+ bool requires_extended_probe);
extern int radeon_ddc_get_modes(struct radeon_connector *radeon_connector);
extern struct drm_encoder *radeon_best_encoder(struct drm_connector *connector);