[Bug 15657] Picture translated to the right over digital output

bugzilla-daemon at freedesktop.org bugzilla-daemon at freedesktop.org
Sun Jul 6 04:41:27 PDT 2008


--- Comment #4 from Josselin Mouette <joss at debian.org>  2008-07-06 04:41:25 PST ---
Created an attachment (id=17552)
 --> (http://bugs.freedesktop.org/attachment.cgi?id=17552)
Working configuration

I finally managed to work around the issue. It is exactly the same as the one
reported with the intel driver:

The problems were the following:
 * The X server does not understand the EDID output returned by the TV. This is
the real issue, and fixing it should make a similar setup work out of the box.
It seems that the TV requests a 1080i (1920x1080 interlaced) mode, and the X
server interprets it as 1920x540. 
 * The default modeline that the X server uses for 1920x1080 when no EDID
information is available is not suitable at all for such a display. I had to
generate another one with very small synchronisation times, and it worked like
a charm. I don’t know whether other brands of TVs are as picky about these
sync times, but if so, maybe the default modelines for 720p and 1080p should
have different characteristics from the modelines used for "monitor"
 * Added modelines are not used unless you specify a new mode name and set
"PreferredMode". I can’t think of any good reason for this; if you specify a
modeline for an existing resolution, it should definitely be used instead of
the default or the detected one.
 * By default, a screen is only associated with the first output of a device,
so the added modeline will only be used by this output. Once you think about
it, it is very well documented so I understand this is intentional, but it is

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