Radeon HD 6620G

[Alex Deucher]

On Thu, Apr 25, 2013 at 4:04 PM, James Cobban <webmaster at jamescobban.net> wrote:
> I am still looking for a working driver for the Radeon HD 6620G.  The AMD
> driver is extremely limited and fails randomly, and the Xorg driver
> consistently does not turn the backlight on for my LCD screen on resume.
> The ability to suspend and resume is absolutely critical on a laptop.
>
> As I have said I would be happy with the current Xorg driver if only there
> were some way to manually turn on the backlight.  I am told that there is no
> manual way to do so, although this strikes me as purism getting in the way
> of practicality,

As I mentioned before, you can manually control the backlight via
either the ACPI backlight interface (if your laptop provides one) or
via the radeon specific backlight controls (if your oem uses the GPU
backlight controller).  If either of these shows up in
/sys/class/backlight/ you can try to control it manually by adjusting
the level in sysfs.  If neither of those work then either is a bug in
one of the drivers that handles the backlight, or your oem has wired
up the laptop in a strange way such that the existing backlight
drivers don't work with it.

Alex