fixed 702188 3.11-1~exp1 thanks Le dimanche 03 mars 2013 à 19:08 +0100, Vincent Blut a écrit : > Package: src:linux > Version: 3.8-1~experimental.1 > Severity: important > > Hi, > > In kernel prior to 3.7 I used to control the brightness through > gnome-control-center (or writing a value in /sys/class/acpi_video0), but since > 3.7 this is broken (ditto for the brightness function keys which are supported > since this version), unless I boot with the '!Windows 2012' kernel > parameter. I guess commit a57f7f9175b8 is the culprit, however I didn't > try to boot with it reverted yet. > > Apart booting with the above kernel parameter, I guess it would be > possible to blacklist the "video" module in order to make the backlight > control fallback to intel_backlight. > > Anyway, I don't know if this issue is exclusively the kernel fault or if > the firmware is at fault too. Also I didn't check if there was a > possibility to add a quirk for this system to avoid it to boot with > the Windows 2012 _OSI deleted. >
Well this seems to be fixed in Linux 3.11, I mean I do not need 'acpi_osi="!Windows 2012"' on the Linux kernel command line to change the backlight level. *However* if I boot with/out this kernel parameter, the kernel reports that I'm using the ACPI backlight interface: $dmesg | grep -i backlight [ 1.785468] asus_wmi: Backlight controlled by ACPI video driver […] I heavily doubt that's the case because the number of possible backlight levels is clearly different if I set the above kernel parameter or not: With acpi_osi="!Windows 2012" → the backlight control interface exposes 6 levels IIRC. Without acpi_osi="!Windows 2012" → 18 backlight levels where 0 = backlight turned off, to me that looks like the Intel backlight interface behavior despite the kernel tells me it's the ACPI one. So when the kernel exposes two backlight control interfaces, is there a way to know which one is in use? Finally I need to find time to bisect to know which commit fixed this stuff because there are a lot of heated discussions around the backlight control interfaces, especially around the ASUS UX31A¹ that I'm using. ¹https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/commit/?id=cb7a386c6c25e85c2710cdb1a498a73794cda660 [merged in 3.12-rc1] To me this commit becomes, de facto, useless because the kernel seems to correctly falls back to the Intel backlight control interface but I may be wrong! Ben, sorry to bother you, I was thinking that you might have cherry picked commit cb7a386c6c25 in 3.11-1~exp1, is this the case? > Thanks and have a nice day, > Vincent -- To UNSUBSCRIBE, email to debian-kernel-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/1382203230.10433.34.camel@lamella
