Hi Lewis et all, On 05/23/2014 02:07 PM, Lewis Toohey wrote: > On 23 May 2014 02:34, Aaron Lu wrote: >> On 05/21/2014 09:02 PM, Lewis Toohey wrote: >>> Hi Aaron >>> >>> I followed your instructions and can report some limited success. I >>> have two interfaces listed in /sys/class/backlight namely: >>> acpi_video0 radeon_bl0 >>> >>> max_brightness for acpi_video0 is 11. Echo-ing new values to >>> brightness appears to have no effect. >>> >>> max_brightness for radeon_bl0 is 255. Echo-ing new values to >>> brightness does adjust the screen brightness as you would expect. >>> >>> Results are the same on both battery and powered. >>> >>> I hope that is useful. >> >> I think Hans' patchset should solve your problem, can you please give it >> a try? You will need to pass the video.use_native_backlight=1 to kernel >> cmdline when testing, thanks. >> >> [PATCH resend 0/4] Make video.use_native_backlight=1 work properly with nouveau >> http://www.spinics.net/lists/dri-devel/msg59941.html >> >> -Aaron > > Aaron > > Thank you for this. Unfortunately I am going to have to ask you for a > bit of help here as I am now, officially, "out of my depth". I > appreciate this is a pain as you will have to take time explaining it > to me and I apologise for that. > > I have figured out how to pass the kernel command line argument, this > is not an issue. > > I have located the patch you refer to here: > https://bugzilla.redhat.com/attachment.cgi?id=894577 > (which I believe is correct) but I cannot figure out how to apply it. That is not the right patch, you need a set of 2 patches. I've attached them to this mail. Note please ignore the numbering starting at 6, these are the 2 patches you need. You will need to build a Linux kernel with these 2 patches applied, see your distributions documentation on how to build a kernel from source. I don't know which distro you are using, I've a Fedora kernel with this patches included available here: http://people.fedoraproject.org/~jwrdegoede/rhbz1093171/ Regards, Hans