Trying to use Radeon driver on Apple eMac

Alex Deucher alexdeucher at
Thu Dec 11 08:48:16 PST 2008

On Thu, Dec 11, 2008 at 2:17 AM, Joseph Adams
<joeyadams3.14159 at> wrote:
> My Xorg.0.log and output of xrandr (in the absence of an xorg.conf)
> can be found at .
> It looks to me like Xorg is adding default modelines that aren't
> appropriate for the internal CRT monitor.  Since my LCD monitor
> supports 1280x1024 resolution that matches one of the default modes
> picked erroneously for the internal CRT monitor, Xorg picks that
> resolution and uses it.  A 1280x1024 external/1280x960 internal
> configuration set up through xrandr does work fine, though.

This is something of an xserver issue.  Most multi-sync CRT's can
support just about any common mode timings, so the xserver adds them
since many users find them useful.  Unfortunately the eMac is
particularly picky about it's modes on the internal monitor.  We may
want to add am output flag the driver can use to tell the server not
to add the default modes for cases like this.  A workaround for the
moment would be to add a filter for eMacs to radeon_mode_valid() to
deny any modes that will not work on the eMac.  Could get tricky

What's happening is that the xserver is trying to set up the largest
clone mode available.  it's matching the 1280x1024 preferred mode from
the external monitor's edid and adding the default 1280x1024 mode
(from the default mode added by the server).  unfortunately the
internal monitor doesn't like this mode.


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