[Intel-gfx] [PATCH 1/2] drm/edid: adjust double-clocked cea modes

[Paulo Zanoni]

2012/5/14 Adam Jackson <ajax at redhat.com>:
>
> ... right after this are the 2800x480 modes.  Are they really 720, 1440,
> or 2880 wide?  Both before and after this change they're 2880 wide, but
> the logic of this change makes me believe they should not be.

These modes you're talking about (10-15, 25-30, 35-38), are even more
different than the ones we're touching. The pixel data can be sent 1
to N times on these modes, not exactly 2 (like on the modes we're
touching). Look at table 18 "Valid Pixel Repeat Values For Each Video
Format Timing" on the spec. Considering that pixels data *can* be sent
1 time on these modes, maybe they will even work out of the box? I
haven't bothered to even try to fix them since I couldn't find any
TV/Monitor that supports them. Anybody here got one? And BTW, why
would I ever want to use 2880x480?

Since we're talking about fixing CEA modes, it might be worth
mentioning that, for now, some modes are defined exactly the same
(like modes 58 and 59), but the spec says that the difference between
these modes is the aspect ratio, which we should specify using AVI
InfoFrames. I couldn't get this working on my monitors (maybe I'm
doing something wrong)... See Table 4 "Video Formats - Video ID Code
and Aspect Ratios".

Yet Another Problem (TM) is that we should be sending the VIC (these
numbers representing the modes) on the AVI InfoFrame too... I have no
idea what problems we can fix with this, but if we discover this is
necessary, we need to figure out in which struct to add this kind of
information to pass to the drivers...

-- 
Paulo Zanoni