intel: lvds-pipe shared with another output?

Eric Anholt eric at
Wed May 14 12:17:34 PDT 2008

On Tue, 2008-05-13 at 17:43 +0200, Simon Pasch wrote:
> Hello,
> We want to use an intel 945gm in a slightly unusual setup here (it's
> for an embedded device):
> Output 1 should be displayed over LVDS and TMDS-1
> Output 2 (right of Output 1) should be displayed over a second
> SDVO-Chip (named Unknown-2 in driver, but seems to work
> out-of-the-box)
> We have successfully used intel-driver 2.3.1 for displaying one single
> output on all screens simultaneously. Displaying two different outputs
> over TMDS-1 and Unknown-2 was successful only if we disabled
> lvds-output first. But we didn't managed to get it working in the
> above mentioned way.
> So the question is:
> Is it possible to share the LVDS-pipe (named "1" by xrandr) with
> another output (for example TMDS-1, which claims to be usable over
> pipe 0 and 1)?
> And, by the way, can LVDS only be used over Pipe 1 because of
> hardware-limitations. or is it only driver-related?  I've seen the
> following code in i830_lvds.c:
>     if (intel_crtc->pipe == 0) {
> 	xf86DrvMsg(pScrn->scrnIndex, X_ERROR,
> 		   "Can't support LVDS on pipe A\n");
> 	return FALSE;
>     }

Both of these are hardware limitations according to the specifications.
Can't do LVDS with any other output on the pipe, and LVDS is only pipe

Eric Anholt                             anholt at
eric at                         eric.anholt at

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