Re: Matrox G550, dual head, 1680x1050

[Petr Vandrovec <vandrove@vc.cvut.cz>]

Geert Uytterhoeven wrote:
> On Tue, 6 Mar 2007, Petr Vandrovec wrote:
>> Hans-J�rgen Koch wrote:
>>> This initializes the primary head correctly. The second head is probably 
>>> wrong, because the monitor's on screen message complains about a non-ideal 
>>> resolution.
>> Second head always starts in 640x480/32bpp.  You have to use fbset to 
>> switch it to different mode, so matroxfb works fine as far as I can tell.
> 
>>> $ fbset -fb /dev/fb1 -g 1680 1050 1696 1050 32 -t 7380 224 32 32 4 136 4
>                                       ^^^^
>>> With that, the image on the second monitor immediately becomes clear, and I 
>>> have a fully working xinerama configuration then.
>> Yes, and this corrects X programming mistake.
>>
>>> As far as I can see, fbset is the only way to initialize the second head 
>>> properly. Neither matroxfb nor mga do it correctly with 1680x1050.
>> Well, fbset == matroxfb, so I do not quite understand your complaint.
> 
> If I followed this discussion correctly, there's still an issue with matroxfb,
> as it doesn't seem to round up xres_virtual to 1696 automatically.
> You have to do that yourself.

Well, as far as I can tell 1680 is legal line length for 32bit color 
mode.  In Hans-Jurgen scenario X program display themselves (otherwise 
fbset would not report 640x480 on /dev/fb1 once X start), and apparently 
screw up rounding.  Having to use 1696 should be necessary only for 
16bpp, and for such case matroxfb already contains code to round up 
value to multiple of 32...

So unless somebody can reproduce problem with using fbdev driver on both 
primary and secondary head I do not believe there is any problem to fix 
on matroxfb side.
								Petr



-------------------------------------------------------------------------
Take Surveys. Earn Cash. Influence the Future of IT
Join SourceForge.net's Techsay panel and you'll get the chance to share your
opinions on IT & business topics through brief surveys-and earn cash
http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV
_______________________________________________
Linux-fbdev-devel mailing list
Linux-fbdev-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/linux-fbdev-devel