http://bugzilla.kernel.org/show_bug.cgi?id=13210
--- Comment #5 from Maxim Levitsky <[email protected]> 2009-04-30 15:41:34 --- (In reply to comment #3) > Yakui, > acpidump can be gotten from bug #13121 > and your suggestion is not helpful for this bug. > > Now, I think we should make clear > 1. if the brightness is changed by BIOS or by AML code. > 2. what does gpm use for brightness control, > /sys/class/backlight/.../brightness vs actual_brightness > > (In reply to comment #0) > > > > Thus a single (say brightness up) event results in brightness going 4 levels > > up: > > > > 1 due to hardware change, > agree > > > 1 for acpi video driver automatic chager, > agree, this can be enabled/disable via brightness_switch_enable. > > > 1 by gpm listening to acpi event device, and finally 1 due to normal > > keypress. > > I'm confused here. > > the "finally 1 due to normal keypress", you mean the input event for the > keypress, right? > how does gpm catch acpi event? or catch what kind of events? > I think these two are the same. I think it uses hal, and it reads directly from /dev/input/eventX interfaces > > IMO, there are three parts in all, when pressing a hotkey > 1. an ACPI interrupt is generated > 2. an ACPI notification is send to ACPI video driver as a result of the ACPI > interrupt > 3. ACPI video driver exports an input event to userspace upon the notification > > Backlight can be changed in either 1(BIOS/AML), 2(ACPI video driver), or > 3(userspace app). > The problem here is that if it's done in step 1, which is out of OS's control, > we should be able to prevent the actions in step 2 and step 3. > And it seems that brightness_switch_enabled and with hal > laptop_panel.brightness_in_hardware flags are just for this purpose. > > If I'm right, the only problem left is that OSD shows incorrect brightness > level, right? > IMO, there could be two reasons. > 1. OSD uses /sys/.../brightness, like you said > 2. when hal laptop_panel.brightness_in_hardware is set, hal just ignore the > event totally, i.e. even not re-query the current brightness level upon this > event. > > this is gotten from your previous email, > ma...@maxim-laptop:~$ grep . /sys/class/backlight/acpi_video0/* > /sys/class/backlight/acpi_video0/actual_brightness:2 > /sys/class/backlight/acpi_video0/bl_power:0 > /sys/class/backlight/acpi_video0/brightness:7 > /sys/class/backlight/acpi_video0/max_brightness:9 > > what does OSD show in this case? a level of 7? > please change the backlight via this sysfs I/F, e.g. echo 4 > > /sys/class/backlight/acpi_video0/brightness, then press the brightness up > hotkey, what does OSD show now? a level of 5 or still 7? I already did that test for myself. OSD shows /sys/class/backlight/acpi_video0/brightness -- Configure bugmail: http://bugzilla.kernel.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug. ------------------------------------------------------------------------------ Register Now & Save for Velocity, the Web Performance & Operations Conference from O'Reilly Media. Velocity features a full day of expert-led, hands-on workshops and two days of sessions from industry leaders in dedicated Performance & Operations tracks. Use code vel09scf and Save an extra 15% before 5/3. http://p.sf.net/sfu/velocityconf _______________________________________________ acpi-bugzilla mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/acpi-bugzilla
