[Intel-gfx] VGA to PAL RGB

Thomas Elsen lists at rivy.org
Tue Aug 26 12:31:37 PDT 2008

Thomas Hilber wrote:
> On Thu, Jul 24, 2008 at 12:21:14PM +0200, Thomas Elsen wrote:
>> I'm trying to get the following modeline to work with my Mythbuntu. This 
>> modeline should be perfect for television sets that understand PAL.
>> Modeline "768x576pali" 14.76  768 789 858 944  576 580 583 625 -hsync 
>> -vsync interlace
> [...]
>> The problem with the current drivers is that the minimal dot clock is 
>> defined as 25Mhz. I'd like to know if this is a hardware limitation and, 
>> if not, what should be done to run the clock at 14,76Mhz.
> [...]
> Yesterday I started to port this thing to intel DDX. Please find
> attached a patch that allows you to use such low dot clocks on intel
> hardware. I don't know what these limits in the standard intel code are
> good
> for. BTW I use a thinkpad with mobile GM965/GL960 chipset for my tests.
> Maybe you must adapt the patch to your needs.
> But there exist still some issues with intel-gfx and interlaced modes:
> Using the overlay XV adaptor I only get a green picture...
> Using the textured XV adaptor the picture is vertically stretched (if
> not
> doubled)...
> So for the moment I stopped further activities with intel-gfx.
> Maybe the situation has improved since xf86-video-intel 2.4.0. I haven't
> had the time yet to give it a try.
> -Thomas
The patch works as expected. I can use lower dot clocks and I can get a 
non interlaced mode to work. The only problem left seems to be the 
interlaced modes. When I'm using interlaced modes, my screens scrolls 
horizontally and my video is not displayed at all when using XvMC.

Any idea about the status of this BR?

Kind regards,
Thomas Elsen

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