Arch Linux

gen2arch

Member

Registered: 2013-05-16

Posts: 182

SOLVED Breakage on Asus UX21A after recent upgrade

After a recent upgrade that brought the kernel to 3.9.2 a lot of things stopped working on my asus zenbook prime: most annoyingly all function keys. They seem like disabled. In xev they don't even produce any event.

This in turn breaks an easy interface to keyboard backlight, screen brightness and sound volume.

I downgraded the kernel to what I had before (3.8.8) and the function keys do work again.

Unfortunately I was unable to circumvent another bug introduced by the upgrade, namely that whenever the machine returns from a blanked out screen, screen backlight is set to max. That cannot possibly be the intended behavior. I get this with journalctl:

archlinux pkexec[1939]:: Executing command [USER=root] [TTY=unknown] [CWD=/] [COMMAND=/usr/bin/xfpm-power-backlight-helper --set-brightness 10]

This is annoying because you have to readjust backlight every time manually.

Can anyone shed some light on this? What parts of the kernel do control this? Or what triggered the modified behavior?

Thanks.

Last edited by gen2arch (2013-05-17 20:07:55)

ewaller

Administrator

From: Pasadena, CA

Registered: 2009-07-13

Posts: 19,784

Re: SOLVED Breakage on Asus UX21A after recent upgrade

archlinux pkexec[1939]:: Executing command [USER=root] [TTY=unknown] [CWD=/] [COMMAND=/usr/bin/xfpm-power-backlight-helper --set-brightness 10]

I would look into pkexec.

Can anyone shed some light on this?

I like the irony

What parts of the kernel do control this?

It doesn't. Well xfpm-power-backlight-helper  changes something in /sys, or makes calls that cause the kernel to do something, but the kernel does not initiate anything.

Edit: Okay, the next question is, "What is invoking pkexec"  I don't know, yet.  What are the 30 or so lines in front of that journal entry?

Last edited by ewaller (2013-05-16 21:19:35)

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gen2arch

Member

Registered: 2013-05-16

Posts: 182

Re: SOLVED Breakage on Asus UX21A after recent upgrade

ewaller, thanks for your reply!

I did a pacman -Qo on the xfpm-power-backlight-helper program an it turns out to be part of xfpm-power-backlight-helper!

So in turn I downgraded to its previous version, an indeed the problem with max'ing screen backlight disappeared. Of course this is no real solution. I was hoping that xfpm-power-backlight-helper ws a script, so I could see what it does, but it is a compiled program.

I'm going to upgrade to the recent version of the kernel in order to see, as you suggested, more journalctl output, but as far as I remember it was non-descript.

By the way: I'm new to arch, as this little ultrabook is the first machine where I did not install Gentoo; what is the easiest method to switch kernels in arch?

Wrt to the function key problem: It seems that a lot of people having issues with that as the new kernel would not display certain files in the sys filesystem used to manipulate these settings. Unfortunately, I have no solution for that.

thanks

gen2arch

Member

Registered: 2013-05-16

Posts: 182

Re: SOLVED Breakage on Asus UX21A after recent upgrade

Now this is really getting weird: I reinstalled the actual kernel 3.9.2, but this time I booted the machine with AC power, -- and everythings works as before, all the function keys, no maxing of backlight.

Shut down the  machine and booting on battery power: same breakage as described in my original post!

Booting, or not, with the machine plugged in triggers the error!

Hints anyone?

gen2arch

Member

Registered: 2013-05-16

Posts: 182

Re: SOLVED Breakage on Asus UX21A after recent upgrade

I mark this issue as solved, though problems remain, as I can affirm the solution padfoot gave in postings #11 and #13 of this thread:

https://bbs.archlinux.org/viewtopic.php?id=162643

Although boot error messages related to asus_nb_wmi remain, a viable solution is to include this driver in the modules array of /etc/mkinitcpio.conf, rebuild the initial ramdisk with mkinitcpio -p linux and copy the built ramdisks over to the ESP.

thanks