Re: [Linux-fbdev-devel] Fixed-frequency monitor, and G45 se

[Petr V. <VAN...@vc...>]

On 25 Oct 01 at 22:32, Carlo E. Prelz wrote:
>     fvs.yres=fvs.yres_virtual=576;
>     fvs.vmode=FB_VMODE_INTERLACED;
> 
> and I have a good image - exactly what I needed. 
> I have one problem, though... I would like to use both screens of a
> Matrox G450 with two independent framebuffers. Well, the first (main)
> screen is set correctly, but it seems that the second one does not
> accept to go interlaced. Is this something well-known? Am I forgetting
> something? 

Well, documentation says that it is possible, but I thought that nobody
uses interlaced picture now... If you want to do some experiments, you
can try:

(0) make sure that yres+upper+lower+vslen is odd
(1) set bit 25 (0x02000000) in register 0x3C10 (== enable interlace)
(2) program register 0x3C28 with start of even field (== leave current value)
(3) program register 0x3C2C with start of odd field (== 0x3C28+vxres*bpp/8)
(4) program register 0x3C40 with value twice as large as currently
    (== line offset)

and you'll see. I'm not sure whether step (4) is needed or not, documentation
is not clear on this.

If you'll manage to create patch, please send it to me.
                                                Best regards,
                                                    Petr Vandrovec
                                                    van...@vc...