Re: atyfb h/vsync polarity

["Antonino A. Daplas" <adaplas@gmail.com>]

On Wednesday 22 June 2005 22:08, Raphael Assenat wrote:
> Hi,
> I am a Linux Sparc64 user, and recently I decided to switch from 2.4
> kernel series to 2.6 series. Everything worked well, but I had trouble
> getting the framebuffer console to work.
>
> In openboot, my monitor worked perfectly. But as soon as Linux
> configured the framebuffer, my monitor would loose sync. I compared the
> output given by fbset on the working configuration (2.4 kernel) and the
> non-working configuration (2.6.12 kernel). Every setting was identical,
> except that the output on 2.4 had 'hsync high'. I tried 'fbset -hsync
> high', but the screen still did not sync, and fbset still did not report
> 'hsync high', as if the setting was ignored.
>
> After digging a little bit, I found this in
> drivers/video/aty/atyfb_base.c:
>
> if(vdisplay < 400) {
> 		h_sync_pol = 1;
> 		v_sync_pol = 0;
> } else if(vdisplay < 480) {
> 		h_sync_pol = 0;
> 		v_sync_pol = 1;
> } else if(vdisplay < 768) {
> 		h_sync_pol = 0;
> 		v_sync_pol = 0;
> } else {
> 		h_sync_pol = 1;
> 		v_sync_pol = 1;
> }
>

I also believe that the above code is not needed.  The appropriate
sync signals are already correctly set (hopefully) from the entries
in the mode database, kernel or user.

Also, if I remember the VGA standards correctly, hsync and vsync
should be high if vyres > 400.

Tony



-------------------------------------------------------
SF.Net email is sponsored by: Discover Easy Linux Migration Strategies
from IBM. Find simple to follow Roadmaps, straightforward articles,
informative Webcasts and more! Get everything you need to get up to
speed, fast. http://ads.osdn.com/?ad_id=7477&alloc_id=16492&op=click