drm/radeon: workaround a hw bug on some radeon chipsets with all-0 EDIDs.
authorDave Airlie <airlied@linux.ie>
Tue, 14 Jun 2011 06:13:55 +0000 (06:13 +0000)
committerDave Airlie <airlied@redhat.com>
Thu, 16 Jun 2011 06:30:54 +0000 (16:30 +1000)
commit4a9a8b71e12d41abb71c4e741bff524f016cfef4
treee5b3589c7568897a2184646665ca2f67257b62a5
parentf49dadb82dde88092827b6d058e7164e75e96759
drm/radeon: workaround a hw bug on some radeon chipsets with all-0 EDIDs.

Some RS690 chipsets seem to end up with floating connectors, either
a DVI connector isn't actually populated, or an add-in HDMI card
is available but not installed. In this case we seem to get a NULL byte
response for each byte of the i2c transaction, so we detect this
case and if we see it we don't do anymore DDC transactions on this
connector.

I've tested this on my RS690 without the HDMI card installed and
it seems to work fine.

Signed-off-by: Dave Airlie <airlied@redhat.com>
Reviewed-by: Alex Deucher <alexdeucher@gmail.com>
drivers/gpu/drm/drm_edid.c
drivers/gpu/drm/radeon/radeon_connectors.c
include/drm/drm_crtc.h