Bug 59671

Created attachment 104651 [details]
An acpi dump from my laptop using acpidump.

Please provide the output of dmidecode and it's better to do a quirk for this machine to use vendor video driver defaultly.

Created attachment 104721 [details]
A dmidecode from my laptop

Hello Lan Tianyu, I have uploaded an dmidecode. I hope that helps.

Regards.

Oh, I realized KDE/xbacklight can't set brightness... I prefer doing it by keys, but I share all I can =).

Regards.

1 Please show me the output of:
$ ls /sys/class/backlight

I saw your post of the arch page, do you have only one file intel_backlight there?

2 Please use acpi_listen to check if any event is received when pressing the backlight hotkey. acpi_listen is provided by acpid package.

Thanks.

1.- This is the output:

acpi_video0  intel_backlight

Yes, I have only one file intel_backlight.

2.- No... I can see CDPLAY, CDSTOP, CDNEXT events, but no anything when I press backlight hotkeys.

Thank you =).

Regards.

(In reply to comment #7)
> 1.- This is the output:
> 
> acpi_video0  intel_backlight

I think this is two :-)

Does manually change brightness using acpi_video0 work?
# cd /sys/class/backlight/acpi_video0
# echo 2 > brightness
# echo 5 > brightness
Any effect?

> 
> Yes, I have only one file intel_backlight.
> 
> 2.- No... I can see CDPLAY, CDSTOP, CDNEXT events, but no anything when I
> press
> backlight hotkeys.

This means we have a bug in hotkey notification, I'll prepare a debug asl file for you to test a moment later.

Can you build kernel from source?

(In reply to comment #8)
 
> I think this is two :-)
> 
> Does manually change brightness using acpi_video0 work?
> # cd /sys/class/backlight/acpi_video0
> # echo 2 > brightness
> # echo 5 > brightness
> Any effect?

No, it has no effect :(. If I not use acpi_osi lines in kernel line in GRUB2, I can change brightness with this method, but in intel_backlight/brightness file.


> This means we have a bug in hotkey notification, I'll prepare a debug asl
> file
> for you to test a moment later.

Ok, I am ready to help :). But I need you explain me how to do this :).

(In reply to comment #9)
> Can you build kernel from source?

I should need to learn it... I think this is enough https://wiki.archlinux.org/index.php/Kernels/Compilation/Traditional . If I don't have to configure anything I think I don't have any problem :).

Regards.

(In reply to comment #10)
> (In reply to comment #8)
> 
> > I think this is two :-)
> > 
> > Does manually change brightness using acpi_video0 work?
> > # cd /sys/class/backlight/acpi_video0
> > # echo 2 > brightness
> > # echo 5 > brightness
> > Any effect?
> 
> No, it has no effect :(. If I not use acpi_osi lines in kernel line in GRUB2,
> I
> can change brightness with this method, but in intel_backlight/brightness
> file.

So only intel_backlight works, right?

> 
> I should need to learn it... I think this is enough
> https://wiki.archlinux.org/index.php/Kernels/Compilation/Traditional . If I
> don't have to configure anything I think I don't have any problem :).

Just remembered no need to compile kernel at this time, override DSDT in initrd should do the trick too. I'll attach a DSDT table named dsdt.aml, please follow the below steps to replace your initrd:
// make a copy of your original initrd, after test, restore it
$ sudo cp /boot/initramfs-xxx.img /boot/initram-xxx.img.orig
// insert the new DSDT table into a new initrd
$ mkdir $HOME/initrd/kernel/firmware/acpi
$ cd $HOME/initrd
// the dsdt.aml is the new DSDT table I'll attach shortly
$ cp dsdt.aml kernel/firmware/acpi
// generate the new initrd
$ find kernel |cpio -H newc --create > new_initrd
// cat it with the original one
$ cat /boot/initramfs-xxx.img >> new_initrd
Now the new initrd is ready, use it to boot the system. Also, make sure to add the following kernel command line, no other command line option required:
acpi.aml_debug_output=1

After boot, press backlight hotkey, and then attach dmesg output here, thanks.
If you have any problem, please let me know.

Created attachment 104921 [details]
Add debug statement in _Q11/_Q12

Add some debug statements in DSDT table to check some value in asl code.

Yes, only intel_backlight works. I have removed all acpi lines in GRUB (only stays the debug one). Intel_backlight method still works, but xbacklight can't set brightness. Dsmeg:

[  115.698208] [ACPI Debug]  String [0x0B] "_Q11, LMST="
[  115.698234] [ACPI Debug]  Integer 0x00000000
[  115.698247] [ACPI Debug]  String [0x0B] "_Q11, OSYS="
[  115.698256] [ACPI Debug]  Integer 0x000007D9
[  115.698268] [ACPI Debug]  String [0x0A] "_Q11, OBV="
[  115.698274] [ACPI Debug]  Integer 0x00000086
[  122.476867] [ACPI Debug]  String [0x0B] "_Q12, LMST="
[  122.476897] [ACPI Debug]  Integer 0x00000000
[  122.476922] [ACPI Debug]  String [0x0A] "_Q12, OBV="
[  122.476930] [ACPI Debug]  Integer 0x00000086

115.* lines are "Brighness down" hotkey, and 122.* "Brightness up" hotkey.

I remember: without acpi lines in GRUB, xev recognize the keys, but OSD brightness only works if I push "alternate-ly" "Brightness down" and "Brightness up" keys. I don't understand, really XD.

Thanks for helping :).

Regards.

According to the debug message, the notification is sent out.

Please add the following content to /etc/X11/xorg.conf(if not exist, just create it):

Section "Device"
Identifier  "Intel Graphics"
Driver      "intel"
Option      "AccelMethod"  "sna"
Option     "Backlight"          "intel_backlight"
Identifier  "Card0"
Driver      "intel"
BusID       "PCI:0:2:0"
EndSection

Then reboot, this time, no kernel command line is required. Let me know if everything works fine, thanks.

It's ok now, but I had to remove

Identifier  "Card0"
Driver      "intel"
BusID       "PCI:0:2:0"

because Xorg told me a parse error: 2 fields identifier. 

So is it no a bug? Is it only an error? In my old installation I have no Xorg.conf for my intel card... It doesn't disturb me but I have to ask it =).

All is OK now. I'm sorry for disturb, guys. I'll save this Xorg safely :).

No problem.

The problem is, userspace(X for example) would pick acpi_video0 interface by default, which is broken on your system. So we have to tell X to use an workable interface, as is done in xorg.conf. Then for backlight brightness change, you have intel_backlight for it; for hotkey notification, you have ACPI for that. This is the current way we workaround backlight problems, maybe we need a better one in the future...

Thanks for testing! I'll close the bug as DOCUMENTED.