https://bugzilla.novell.com/show_bug.cgi?id=578578 https://bugzilla.novell.com/show_bug.cgi?id=578578#c6 Michael Chang <mchang@novell.com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jlee@novell.com --- Comment #6 from Michael Chang <mchang@novell.com> 2011-08-24 05:53:16 UTC --- Hi Matthias, Yes. This is related with "Intel backlight combination mode", that is the backlight brightness level can be changed via LPBC (that is the PCI configuration register your workaround uses) OR i915's BLC_PWM_CTL register. As far as I know, we have to access both registers at the same time to guarantee a reasonable dynamic backlight range (The LPBC is acts a multiplier of 255 with BLC_PWM_CTL value). This combination mode is used on older Intel graphics and yours is fall into this category (GMA4500 is used in Montevina platform, we ever came across similar issue on this hardware). For modern Intel graphics, the LPBC register was obsoleted. I also CC Joey Lee as he is maintainer of ACER acpi/wmi driver. This might also be an ACPI issue as these function keys would trigger SCI events (Q event) to execute corresponding ACPI method (Q method) an change the backlight (via the opregion or whatever means) in it. First, it would be good if you could help to provide dmesg while your are changing the backlight, whith following kernel command-line parameter. drm.debug=0x02 I would suggest a step, for example ..like $ dmesg -c $ xrandr --output LVDS1 --set BACKLIGHT 6 $ xrandr --output LVDS1 --set BACKLIGHT 9 $ dmesg > /tmp/xrandr-backlight.log Thanks. :) Thanks. :) -- Configure bugmail: https://bugzilla.novell.com/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug.