[PATCH] matroxfb: fix DVI setup to be more compatible

[PATCH] matroxfb: fix DVI setup to be more compatible

There has been a longstanding problem with the Matrox G450 and perhaps
other similar cards, with modes "above" 1280x1024-60 on ppc/ppc64 boxes
running Linux.  Higher resolutions and/or higher refresh rates resulted in
a very noticably "jittery" display, and sometimes no display, depending on
the physical monitor.  This patch fixes that problem on the systems I have
easy access to...

I've tested with SLES9SP3 (2.6.5+ kernel) and 2.6.16-rc6 custom kernels on
an IBM eServer p5 520 w/G450 (a.k.a GXT135P on IBM's ppc64 systems), and a
colleague of mine (Ian Romanick) tested it successfully on an Apple ppc32
box (w/GXT135P).  I also tested it on IA32 box I have with a GXT135P to
verify that it didn't obviously break anything.  In my testing, I covered
single-card, single and dual-head setups using both HD15 and DVI-D signals,
on both the IA32 and ppc64 boxes.  While everything appeared fine on both
boxes, I did encounter one problem: I can't get any signal on the DVI-D
output on the ppc64 box.  However, this is also the case without my patch.

I just noticed that screen-blanking only occurs on the primary display as
well.

Signed-off-by: Paul A. Clarke <pc@us.ibm.com>
Signed-off-by: Ian Romanick <idr@us.ibm.com>
Signed-off-by: Petr Vandrovec <petr@vandrovec.name>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>