Hal and Xorg output devices

Jon Smirl jonsmirl at gmail.com
Wed Feb 23 10:21:02 PST 2005


On Wed, 23 Feb 2005 19:53:32 +0200 (IST), Ely Levy
<elylevy at cs.huji.ac.il> wrote:
> I was wondering about that as well, I guess it depends if we are going
> to completly move to xgl or just give it as another option.
> What do you mean by lower level?in kernel space?I don't think that would
> be wise especialy if we want to have long exeption list.
> does it have to happen in lower level?Maybe it should be like hotplug
> or udev?

The current plan for mode setting is to use a root priv helper app to
generate the list of legal modes. The list can come from DDC or a /etc
file. The list is then set into the fbdev driver via a sysfs
attribute, modes, which only root can write. Running the app for
generating the list is trigger via a hotplug event when the module is
loaded or if the hardware supports it, an interrupt generated by a
monitor switch (radeon has this).

Another sysfs variable, mode, is then used to set the mode. Ownership
of mode is assigned via pam at login to the active user. Take one of
the mode names from the list in 'modes' and copy it to 'mode' that
will allow you to set modes without the need to be root. This is a
major step in removing the need for X to run as root. Since the list
is constrainted you can't set a mode that will blow up your monitor as
a normal user.

If anyone wants to work on the base layers of XGL, we can use all the
help we can get.

-- 
Jon Smirl
jonsmirl at gmail.com



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