drm/i915: clear the entire sdvo infoframe buffer
Like in the case of native hdmi, which is fixed already in
commit
adf00b26d18e1b3570451296e03bcb20e4798cdd
Author: Paulo Zanoni <paulo.r.zanoni@intel.com>
Date: Tue Sep 25 13:23:34 2012 -0300
drm/i915: make sure we write all the DIP data bytes
we need to clear the entire sdvo buffer to avoid upsetting the
display.
Since infoframe buffer writing is now a bit more elaborate, extract it
into it's own function. This will be useful if we ever get around to
properly update the ELD for sdvo. Also #define proper names for the
two buffer indexes with fixed usage.
v2: Cite the right commit above, spotted by Paulo Zanoni.
v3: I'm too stupid to paste the right commit.
v4: Ben Hutchings noticed that I've failed to handle an underflow in
my loop logic, breaking it for i >= length + 8. Since I've just lost C
programmer license, use his solution. Also, make the frustrated 0-base
buffer size a notch more clear.
Reported-and-tested-by: Jürg Billeter <j@bitron.ch>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=25732
Cc: stable@vger.kernel.org
Cc: Paulo Zanoni <przanoni@gmail.com>
Cc: Ben Hutchings <ben@decadent.org.uk>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>