Hi Joey , > Per my understood, EC firmware should change brightness but didn't do > that, another > way is touch i915 register in _BCM. how do we do this ? you mean change the _BCM implementation ? > > Acer machine provide a broken _BCM implementation and they didn't test > it. > > > > > By ' ACPI interface' , I mean 'acpi_video0' inside the > > > > /sys/class/backlight. I havn't tried the /sys/class/backlight interface > > > > directly . I will try that also. > > > > > > So writing values into /sys/class/backlight/acpi_video0/brightness does > > > nothing? > > > > > > No change in value when writing > > to /sys/class/backlight/acpi_video0/brightness. > > > > Another thing is that when i did boot with acpi_backlight = 'acer_wmi' , > > in new kernel (3.3.0-rc7) , it shows following messages , > > > > [ 8.350825] wmi: Mapper loaded > > [ 10.363975] acer_wmi: Acer Laptop ACPI-WMI Extras > > [ 10.396186] acer_wmi: Function bitmap for Communication Device: 0x91 > > [ 10.396385] acer_wmi: Brightness must be controlled by generic video > > driver > > > > Also there was no interface inside /sys/class/backlight for acer_wmi. > > > > Yes, acer_wmi support backlight control with AMW0 interface, your > machine didn't have AMW0 interface. > > Normally, backlight should control by standard acpi interface. > > > I also tried writing directly to Embedded controller register .But no > > change. > > The machine has broken _BCM method, because EC should do something after > _BCM changed EC register. Thanks , Pradeep Subrahmanion -- To unsubscribe from this list: send the line "unsubscribe linux-fbdev" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
