/sys/class/backlight gone!

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Vidigal
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Joined: 2012/08/01 14:45:26

/sys/class/backlight gone!

Post by Vidigal » 2012/08/06 17:33:17

Hey, everything alright? I had a problem with my intel graphic card (i think...).
My note is a HP Pavilion dm4-1075br with Windows7 and CEntOS.

I installed CEntOS 6.2 (now 6.3) in with basic video driver. With that, I had this xorg.conf:
[code]Section "Device"
Identifier "Videocard0"
Driver "vesa"
EndSection[/code]

Them, I changed the driver to intel:
[code]Section "Device"
Identifier "Videocard0"
Driver "intel"
EndSection[/code]

And add acpi_brightness=vendor as a kernel parameter, so the brightness of the screen wouldn't be 0.
( Before I used to change the brighteness value at /sys/class/backlight/acpi_video0 beacuse the backlight was off ).
It was working all fine. I installed some compiz-plugins and etc, all working very fine.
Then, some hours later, I tried to boot and the GUI didn't loaded, I could only use the text mode...

I changed the drive to vesa again and I noticed that /sys/class/backlight was empty!
GUI working, but I need (and like) the benefits of the intel driver...
What can I do now? =(
I really don't want to reinstall my OS once more...

pschaff
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/sys/class/backlight gone!

Post by pschaff » 2012/08/06 19:37:59

First thing I'd try would be to rename /etc/X11/xorg.conf to some backup name and reboot. You could also try the [url=http://elrepo.org/tiki/xorg-x11-drv-intel]ELrepo xorg-x11-drv-intel driver[/url]

Were you using the vesa driver due to problems on the initial install?

Vidigal
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Joined: 2012/08/01 14:45:26

Re: /sys/class/backlight gone!

Post by Vidigal » 2012/08/06 19:49:47

Thanks for the reply!

Well. I tried backing up the xorg.conf and rebooting. Nothing =/
Then I tried to install xorg-x11-drv-intel-2.16.0-4.el6.x86_64, but it was already installed.

Yes, I initially installed with vesa because the "normal" installation had no backlight.
Then I changed to intel and worked great.
And, some shutting offs and turning ons after, the backlight folder was empty and the GUI wouldn't start.
So back to vesa.

pschaff
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Re: /sys/class/backlight gone!

Post by pschaff » 2012/08/06 19:58:01

Seems lots of things broke with 6.3. A new version of the Intel driver is on the ToDo list.

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TrevorH
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Re: /sys/class/backlight gone!

Post by TrevorH » 2012/08/06 20:00:17

Could try modprobe'ing some of the .ko files that come up in the list from `locate backlight` too. No idea if they'll help...

Vidigal
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Re: /sys/class/backlight gone!

Post by Vidigal » 2012/08/06 20:03:16

I don't know, it was working quiet well...

Sorry, but I don't know nothing about modprobing or .ko files =/
Never "played" with them.

Vidigal
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Re: /sys/class/backlight gone!

Post by Vidigal » 2012/08/06 20:14:41

I was thinking to just put what was missing at the backlight folder...
But I not very confident that that's the only problem...

Could someone send me an e-mail with the directory /sys/class/backlight/acpi_video0?

pschaff
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Re: /sys/class/backlight gone!

Post by pschaff » 2012/08/06 20:26:48

The /sys directory structure is automatically created on the fly. You cannot successfully recreate portions of it manually.

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TrevorH
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Re: /sys/class/backlight gone!

Post by TrevorH » 2012/08/06 20:27:37

The problem is that anything under /sys or /proc is an artificial file that doesn't really exist. Anything there is created by the kernel or a kernel module hence my suggestion to look at what .ko files (kernel modules) are listed by `locate backlight` and then use e.g. `modprobe lcd` to load them and see if anything appears in that /sys directory.

Vidigal
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Re: /sys/class/backlight gone!

Post by Vidigal » 2012/08/06 20:43:06

Got it...
Well, I searched and still didn't find where are those .ko files

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