W dniu 29 czerwca 2009 18:08 użytkownik Egbert Eich <eich@suse.de> napisał:
Rafa? Mi?ecki writes: > Currently we don't try to control backlight after detecting > (RHDRegRead(Output, RV620_LVTMA_BL_MOD_CNTL) & LVTMA_BL_MOD_EN) == 0 > > This assumption is quite wrong, because in some (many?) cases we can > just change this one bit and control backlight without problem. > Confirmed to work on M82==RV620.
This is possible but there is no guarantee. It could also be controlled by some OEM specific mechanism. In those cases we cannot control backlight, if at all it can be controlled over ACPI.
What do you mean by "OEM specific mechanism"? Just ACPI? Or something more? What will happen if we try to control (change) backlight on system where it is already controled by ACPI? Can this cause any unstability? Can ACPI control backlight using something else that registers we touch in radeonhd's code?
To not expose a backlight property if we cannot control it anyway I had decided to use this check.
I can control backlight this way anyway. So this is not right check. It cuts off control on system where it actually works fine. And we already know it's not only my specific case.
We could fall back to AtomBIOS controlled backlight in cases where we are not sure as this might be programmed correctly for the system in question - however to implement this would require some extra work as in the hard coded cases the needed data structures have not been set up.
Why AtomBIOS would be safer to use than using registers? What AtomBIOS command would you actually like to call? That whole AtomBIOSScratch code looks really messy for me. -- Rafał Miłecki -- To unsubscribe, e-mail: radeonhd+unsubscribe@opensuse.org For additional commands, e-mail: radeonhd+help@opensuse.org