The end of user-space mode setting? [LWN.net]

The end of user-space mode setting?

Posted Jan 19, 2010 4:34 UTC (Tue) by thedevil (guest, #32913)
Parent article: The end of user-space mode setting?

Uh-oh.

This will be a major headache for me, because this will force me to upgrade xorg if I want to upgrade the kernel. And I will let the new xorg on my boxes over my cold dead body - with its gratuitous dependencies on hal and *-kit and I don't know what else, plus its needlessly changed defaults.

I wonder if anyone else cares about this?

The end of user-space mode setting?

Posted Jan 19, 2010 7:23 UTC (Tue) by rahulsundaram (subscriber, #21946) [Link] (5 responses)

Actually with the latest Xorg, the dependency on HAL is being removed since
HAL itself is now deprecated in favor of udisks, upower and just udev
itself. There are no direct dependencies on *Kit either. So you are
mistaken and can safely upgrade if these were your only objections.

The end of user-space mode setting?

Posted Jan 21, 2010 6:14 UTC (Thu) by thedevil (guest, #32913) [Link] (4 responses)

The version now in Debian unstable is 7.5 and it still depends on HAL.

The end of user-space mode setting?

Posted Jan 21, 2010 7:58 UTC (Thu) by nix (subscriber, #2304) [Link] (2 responses)

The libudev patches were still being revised as of a few weeks ago: the
latest stable X server does indeed still depend on HAL. But you can
configure it out (and given how crashy HAL is I do so as a matter of
course: say what you like about libudev it's never caused programs to
coredump on me).

The end of user-space mode setting?

Posted Jan 21, 2010 18:16 UTC (Thu) by Pc5Y9sbv (guest, #41328) [Link] (1 responses)

You would be amused to see what havoc udevd and xorg are causing for people with Fedora 12 on some Intel integrated graphics chipsets.

Somehow X, udevd, and apcupsd of all things are going crazy on my media-center PC after every reboot. I have to kill off the udevd processes and sometimes apcupsd in order to get X to stop re-detecting its outputs in a flood.

The end of user-space mode setting?

Posted Jan 22, 2010 0:00 UTC (Fri) by mjg59 (subscriber, #23239) [Link]

It's not an xorg or a udev issue - a bug in the kernel is causing the hotplug interrupt to fire
continuously, which results in the kernel delivering millions of messages to userspace. These are
processed by udev, which understandably consumes CPU in the process.

The end of user-space mode setting?

Posted Jan 26, 2010 12:40 UTC (Tue) by daenzer (subscriber, #7050) [Link]

The dependency on hal is gone since xserver-xorg 1:7.5~2.

The end of user-space mode setting?

Posted Jan 19, 2010 9:38 UTC (Tue) by nix (subscriber, #2304) [Link] (5 responses)

this will force me to upgrade xorg if I want to upgrade the kernel

Hardly. Userspace modesetting is a *userspace* thing, inside the X server. If you don't upgrade X, you get UMS just as always.

The end of user-space mode setting?

Posted Jan 20, 2010 16:15 UTC (Wed) by MisterIO (guest, #36192) [Link] (4 responses)

I doubt it's that simple. If the kernel supports only KMS, it will obviously try to do the MS itself and the old X will try to do MS too. I can see some problems there.

The end of user-space mode setting?

Posted Jan 20, 2010 20:02 UTC (Wed) by nix (subscriber, #2304) [Link] (3 responses)

I doubt modesetting will ever be mandatory on graphics cards that support
a text mode at all. (People have been saying that cards with no text mode
support are just around the corner for years, but I've never seen one
outside a Sun workstation.)

The end of user-space mode setting?

Posted Jan 20, 2010 20:03 UTC (Wed) by nix (subscriber, #2304) [Link] (2 responses)

That is, of course, that I doubt that *kernel* modesetting will ever be
mandatory on cards with hardware text mode support, simply because all the
kernel needs to do to disable kernel modesetting on a particular card is
to do nothing. Breaking that would be pointless.

The end of user-space mode setting?

Posted Jan 26, 2010 12:43 UTC (Tue) by daenzer (subscriber, #7050) [Link] (1 responses)

While that's true, at the very least it would mean no 3D acceleration, in some cases no acceleration at all.

The end of user-space mode setting?

Posted Jan 27, 2010 21:16 UTC (Wed) by nix (subscriber, #2304) [Link]

Certainly on newer cards, yes. But, again, if you have a new card, you
probably have a new machine as well, and it's quite likely you *need* a
new kernel anyway. (And if you're changing the graphics card in an
existing machine, you can be assumed to be some variety of geek and thus
capable of building one.)