Bug 60654

Do you have problems adjusting backlight manually or through the ambiant sensor or both? And your system has only one graphics card, right?

Adjusting backlight manually is impossible, but the Fn keys associated are recognized by system.

Adjusting with the ambiant sensor is functionnal, but not after a suspend/resume of system.

My system have one only card : nVidia Quadro 1000m with nouveau driver. No Optimus or similar systems.

Thanks.

(In reply to Charles-Antoine Couret from comment #2)
> Adjusting backlight manually is impossible, but the Fn keys associated are
> recognized by system.

What do you mean by impossible, is there any interface under /sys/class/backlight?

> 
> Adjusting with the ambiant sensor is functionnal, but not after a
> suspend/resume of system.
> 
> My system have one only card : nVidia Quadro 1000m with nouveau driver. No
> Optimus or similar systems.

OK, I see.

I have acpi_video0 folder in /sys/class/backlight. But xbacklight for example or write in /sys/class/backlight files do nothing.

In the web, modify these files are an effect on backlight.

I think we have there problems here:
1 ACPI video module can't control backlight(this depends on your BIOS providing correct ACPI control methods);
2 nouveau driver doesn't provide a backlight control interface;
3 ambient function control stops working after resume.

I'll only track problem 1 here. For 2, you can file a bug in drivers/video(DRI-non Intel) category I think; for 3, you can file a bug in drivers/platform_x86 I think.

acpidump please, let's see if BIOS provides us the correct control methods:
# acpidump > acpidump.txt

Created attachment 107053 [details]
acpidump

With acpi_listen I have the results for the Fn keys :

[root@DiNozzo ~]# acpi_listen 
video/brightnessup BRTUP 00000086 00000000 K
video/brightnessdown BRTDN 00000087 00000000 K

Ok, the bug https://bugzilla.kernel.org/show_bug.cgi?id=60659 after our discussion find a potential solution.

With acpi_backlight=vendor option, the Fn keys don't work (and I though the problem it was not solved). But, /sys/class/backlight/nv_backlight/ folder appeared and modify these files work ! Or use a graphical bar like GNOME parameter.

But, the Fn keys are not recognized by the system with this option.
Where is the problem ?

With acpi_backlight=vendor option, can acpi_listen receive events?

Hum, interesting.
I test the acpi_backlight=vendor option during 2 years, without success. And now, the Fn+Keys are functional ! A recent update ? I don't know. It's very curious.

But, another thing, if I put the max or min value (via Fn+Keys, Gnome tools or /sys files), my screen began black. Entirely black. It's a normal comportment ?

I found the problem.
My precedent kernel was 3.11-rc3 but an update changed to 3.10.x version.

I have the problem with the 3.11-rc3, the 3.10.x can used the Fn+keys.

I can compile and test the 3.11-rc4 kernel this evening to see if the problem is solved in the future mainline branch.

And no, acpi_listen not works for these keys but works for others :

[root@DiNozzo ~]# uname -a
Linux DiNozzo 3.11.0-rc3 #1 SMP Mon Jul 29 18:51:26 CEST 2013 x86_64 x86_64 x86_64 GNU/Linux
[root@DiNozzo ~]# acpi_listen 
button/volumedown VOLDN 00000080 00000000 K
button/volumeup VOLUP 00000080 00000000 K

Test with 3.11-rc4 : not functional, like rc3…

The .config between 3.10 and 3.11 kernel are identical, the difference are new options with default value.

(In reply to Charles-Antoine Couret from comment #11)
> I have the problem with the 3.11-rc3, the 3.10.x can used the Fn+keys.

Please test if v3.11-rc1 has problems with Fn keys, and if yes, possible to do the bisect?

(In reply to Charles-Antoine Couret from comment #10)
> But, another thing, if I put the max or min value (via Fn+Keys, Gnome tools
> or /sys files), my screen began black. Entirely black. It's a normal
> comportment ?

When you set the min value though sysfs, what's exactly the value, zero? If it is zero, this may be expected. For max value, I don't think this is correct...I suppose you are using nouveau interface, and I would suggest you(again) to file a bug there(or continue the conversion with your already filed one) about this problem. Anyway, max value shouldn't black screen, right? So just consult them about this behavior, I don't know much about nouveau driver.

Test with 3.11-rc1 : same problem

I have compiled myself the kernel 3.10.5 (and not the Fedora version) and I can with it to change blacklight with Fn+keys.

I can learn to do the bisect and help to solve that.

Yes, the min value is 0, and the max value is 100.
I will file a new bug. ;)

Thank you for all.

Since this is a HP notebook, I would like you to test if reverting the below commit on top of v3.11-rc1 could fix the problem:

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=b253c9d1d858a3f115f791ee4fe2b9399ae7dbbd

Yes, if I removed this patch, the problem is solved.

Bug #60670 is used to track this regression, please follow that bug there.

*** This bug has been marked as a duplicate of bug 60670 ***