Monitor on DVI-I not detected

Daniel Stone daniel at
Fri Apr 13 03:51:14 PDT 2007

On Fri, Apr 13, 2007 at 12:40:47PM +0200, Matthias Hopf wrote:
> I should read more code...
> radeon_display.c:389
>         /* This doesn't seem to work reliably (maybe worse on some OEM cards),
>            for now we always return false. If one wants to connected a
>            non-DDC monitor on the DVI port when CRT port is also connected,
>            he will need to explicitly tell the driver in the config file
>            with Option MonitorLayout.
>         */
> The code that is disabled in that function looks pretty bitrotten as
> well, it only has one code path for R200 and one for "other" (R100?
> R300? R400?) hardware. It apparently hasn't been enabled for a long
> time.
> Any caveats with enabling the currently disabled code? Except that it
> might turn on a CRTC even if a monitor is *not* present? Or may it crash
> the hardware? Probably nobody knows ;)

Well, it's not just turning on a CRTC, but if you assume it's present
when it's not, then you limit mode validation to the intersection of the
two monitors.  And if DDC fails, then that means the default modes, i.e.

Personally, I think it's best left as is (people connecting
non-DDC-capable monitors -- i.e., monitors that need manual
configuration anyway -- to DVI ports get to configure it, rather than
people who don't having to manually override it).

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