Ubuntu
xserver-xorg-video-ati package

  1. Bug #160871
  2. Comment #28

Comment 28 for bug 160871

Revision history for this message
In , agd5f (agd5f) wrote :

Created an attachment (id=18465)
Always add the screen modes to LVDS

(In reply to comment #2)
> Ah, thanks for the explanation!
>
> But why does NoDDC make it work for these guys? I'd have expected the opposite
> based on this description.

Because in that case the driver ignores the edid and just adds the modes defined in the screen section which may include non-native modes.

>
> Also, if EDID only gives one resolution and the scaler should be used for the
> others, why aren't scaled resolutions provided through xrandr in this case?
>

We rely on the EDID unless it's not available. The question is which modes should we add by default? 800x600? 1024x768? 1152x864? I suppose we could always add the screen modes even when an EDID is present (maybe just for LVDS). I'm not sure what the best solution is. The attached patch always adds the modes specified in the screen section to LVDS outputs.

Note that users can still add new modes at runtime using xrandr:
xrandr --newmode 800x600 38.25 800 832 912 1024 600 603 607 624 -hsync +vsync
xrandr --addmode LVDS 800x600