[Libdlo] serverlayout issues with intel and displaylink configuration

Jelle de Jong jelledejong at powercraft.nl
Wed Oct 13 01:10:28 PDT 2010

Dear Bernie,

On 09-10-10 03:28, Bernie Thompson wrote:
> On 08-10-10 15:23, Jelle de Jong wrote:
>> My major issues is that my displaylink device is not used when it is not
>> the first found screen section in the serverlayout section of my xorg
>> configuration.
> I don't know about this either.  The group I'd recommend posting to is
> http://lists.freedesktop.org/mailman/listinfo/xorg, to see if this is
> the expected behavior or if anyone has any suggestions.  The info you
> posted here is good -- they may also want /var/log/Xorg* logs.
> This would be good, too, because it would be wonderful to get more
> awareness going of the multiple USB display scenario among the xorg
> crowd. There may be simple answers out there for some of the common
> questions.

I did some more testing last week and I figured out something else.

I switched the "displaylink" driver for the "fbdev" driver both the
latest plugable git. I discovered the fbdev driver does the same
unloading of drivers as the intel driver.

(++) FBDEV(0): DPI set to (133, 133)
(II) Loading sub module "fb"
(II) LoadModule: "fb"
(II) Loading /usr/lib/xorg/modules/libfb.so
(II) Module fb: vendor="X.Org Foundation"
    compiled for 1.7.7, module version = 1.0.0
    ABI class: X.Org ANSI C Emulation, version 0.4
(II) UnloadModule: "intel"
(II) Unloading /usr/lib/xorg/modules/drivers/intel_drv.so
(==) FBDEV(0): Backing store disabled
(==) FBDEV(0): DPMS enabled
(==) RandR enabled

So fbdev unloads the intel driver causing the intel display not to
load... The same happens when using the intel devices as the first
screen in the serverlayout and the displaylink devices as seconds.

Is this some feature in the Xorg drivers... I have not yet mailed the
Xorg list. I will try to find some time for this on the end of this week.

Furter more I talked with the XFCE developers about the XFWM (window
manager) and problems with Xinerama. After some discussion it became
very very clear that Xinerama will never be supported any more and that
RandR is the way to go.


When will there be a RandR 1.2 compatible Xorg driver for displaylink
devices? I suspects this will solve a lot of issues and also gather
support from the Xorg developers to help solve some issues.

With kind regards,

Jelle de Jong
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