Interlace modes with r600 KMS

[Marius Gröger]

Am 07.09.2010 16:52, wrote Alex Deucher:
> 2010/9/7 Marius Gröger<marius.groeger at googlemail.com>:
>> Hi All,
>>
>> I'm not able to use interlace modes (r600 KMS from d-r-t, HDMI output, Xorg
>> stack on xorg-edgers, Ubuntu lucid). All interlace modes which are defined
>> in EDID seem to be pruned and don't appear in xrandr. Manually adding a mode
>> using xrandr does work, and the TV set detects the mode, but the image shows
>> horizontal lines. No crash though.
>>
>> Interlace modes did use to work fine in the past, but I don't know when they
>> ceased to function.
>>
>> What is the status of interlace modes on this kind of setup? What more tests
>> or logs would be helpful to analyze the problem? What are other people's
>> experiences with this?
>
> This isn't a driver bug as far as I can tell.  At some point the
> Xserver started purging interlaced modes.  See this bug:
> https://bugs.freedesktop.org/show_bug.cgi?id=29591

Thanks for the pointer. I did look into the xserver sources a bit and 
while I'm far from understanding exactly what's going on, it seems like 
the server is relying on output->interlaceAllowed and 
output->doubleScanAllowed. Aren't these bools in the domain of the 
display driver (granted, this wouldn't be the radeon module but the 
xf86-video-ati driver)?

Also, as I wrote, the purging seems to be half-done, since I am able to 
manually add an interlaced mode. But since that mode doesn't work 
properly - does the radeon module support interlaced modes? Is there a 
non-X way to verify this?

Regards
Marius