How to setup independent screens with the Intel driver?

Boszormenyi Zoltan zboszor at
Sat Oct 31 03:03:50 PDT 2015

2015-10-30 20:08 keltezéssel, Chris Wilson írta:
> On Fri, Oct 30, 2015 at 08:00:46PM +0100, Boszormenyi Zoltan wrote:
>> 2015-10-30 19:15 keltezéssel, Chris Wilson írta:
>>> On Fri, Oct 30, 2015 at 06:17:50PM +0100, Boszormenyi Zoltan wrote:
>>>> In my case with this particular POS machine, the intended primary display,
>>>> the built-in LVDS with a touchscreen attached is apparently wired to pipe 1.
>>>> With this driver behaviour, I can't configure it to be kept as the default :0.0 screen
>>>> if an external display is plugged in. Can this behaviour be changed?
>>> It would need another user parameter. There are several technical
>>> limitations that make automatic assignment difficult. So try
>>> commit 94d271b239d358f71ae0bcfcc31422a569d73d41
>>> Author: Chris Wilson <chris at>
>>> Date:   Fri Oct 30 18:07:37 2015 +0000
>>>     sna: Allow pipes to be manually assigned to ZaphodHead
>>> -Chris
>> Thanks for your work, I just tested it. At startup, it seems to work:
>> 1. it doesn't complain about invalid pipe
>> 2. cursor appears on :0
>> 3. application appears on :0
>> Then as soon as I touch the touchscreen, the cursor jumps to :1 and
>> further cursor movements are on :1 from that point.

Obviously I meant ":0.1", not ":1" here.

> I'm baffled. xinput fun?

The "as soon as I touch the touchscreen" statement needs to be corrected.
The error occurs if the :0.1 screen uses a larger resolution than :0.0

I experimented a little more and I found that the touchscreen still reports
coordinates scaled according to the larger screen resolution, in this case
the native 1920x1080 on the external screen.

If I touch the touchscreen outside the 1024x768 area or use a mouse and
move the pointer outside the first screen, then the pointer jumps to :0.1
and appears there at a position just like if :0.0 was overlayed on :0.1.

If I force Screen 1 to have the same or lower resolution than Screen 0,
then obviously the pointer cannot leave Screen 0 and this mouse pointer
bug doesn't occur.

So, yes, "xinput fun".

But in practice, this will be enough since with the POS software we don't
use resolutions higher than 1024x768.

Thanks again for your driver fix!

Best regards,
Zoltán Böszörményi

More information about the xorg mailing list