* Joey Lee -- Sunday 08 May 2011:
於 六，2011-05-07 於 22:22 +0200，Melchior FRANZ 提到：
It has turned out that acpi key events seem to be handled correctly and even the state of /sys/class/backlight/acer-wmi/brightness is
That's interesting for acer-wmi generated brightness interface when this machine declare acpi brightness interface in DSDT.
I'm sorry to give contradicting info. Yesterday I saw a subdir acer-wmi (or acer_wmi) in /sys/class/backlight/ during one of my tests (with/without acer_wmi, with/without acpi_osi=Linux). Now I left acpi_osi=Linux away and allow acer_wmi, and it's subdir acpi_video0. Next time I'll make notes.
Does it work to you direct control brightness by access by /sys/class/backlight/acer-wmi/brightness ?
No. A number written to this virtual file is accepted and remembered, but it doesn't actually change the brightness. It takes setpci to do that.
As I remember, use setpci to control brightness is not recommended because BIOS or ACPI will also touch brightness level. That will be better control brightness by the function that was provided by BIOS. e.g. ACPI or WMI interface, or direct control by EC.
Well, sounds plausible. And I wouldn't do it if it weren't the only way at the moment. :-)
That means that will be better fix your Fn key control brightness like before, you just need press Fn key to change brightness and don't need have any workaround.
OK. I have added a lot of debug messages to intel_panel.c yesterday. All it told me was that it seems to work correctly wiht acpi_osi=Linux. Except that it doesn't actually change the brightness. Without acpi_osi the functions aren't called at all and none of my messages showed up.
Looks like current status is we try to fix bko#31522 but the patch causes your brightness no work by press Fn key even with acpi_osi=Linux. Does it right?
The history is: with acpi_osi=Linux everything worked with 2.6.38-rc8. With 2.6.38 the screen stayed black. The patch that only ignored lbpc=0 worked (IIRC) including key adjustment. Later patches broke keys.
replace acpi_osi=Linux by acpi_osi="!Windows 2006"
Does it also works to you for backlight control?
No, doesn't work.
m.