How do I manually turn on the light
alexdeucher at gmail.com
Wed Feb 13 15:33:45 PST 2013
On Mon, Feb 11, 2013 at 12:49 PM, James Cobban
<webmaster at jamescobban.net> wrote:
> On 13-02-11 08:32 AM, Alex Deucher wrote:
> On Sat, Feb 9, 2013 at 4:03 PM, James Cobban <webmaster at jamescobban.net>
> I am running Ubuntu 12.10 on a Dell laptop with VGA compatible controller:
> Advanced Micro Devices [AMD] nee ATI BeaverCreek [Mobility Radeon HD 6620G].
> The Xorg driver works well except that when I close and reopen the laptop
> and the system resumes the light is not turned on to illuminate the LCS
> display. Can I manually turn the light on? If so how? I don't see any
> activity on related bugs since 2010.
> I have had to switch back to the proprietary fglrx driver despite its
> problems because being able to close and reopen my laptop is higher priority
> than the improved display characteristics of the Xorg driver.
> What kernel are you using? Does manually adjusting the backlight
> controls after resume fix the issue? Are you using the acpi backlight
> interface or the radeon specific backlight interface? Open a bug
> (https://bugs.freedesktop.org) and attach your xorg log and dmesg
> Ubuntu 12.10 with kernel 3.5.0-23-generic. I am just running with whatever
> configuration the Ubuntu "Additional Drivers" graphical tool activates. I
> do not know what that is. I have no idea how to manually adjust the
> backlight controls, but the light is completely off, so I think that would
> be pointless. I tried using "radeontool light on" to turn the light on,
> because I could see that command being issued by the lid.sh script, but that
> did nothing. I am not familiar with the capabilities of the acpi interface.
radeontool won't do any good for your chip.
> I just want to turn the light on! I would not be asking if I knew what to
> do. I do not believe there is an intrinsic problem that needs a bug fix.
In most cases the driver is able to resume fine and bring back the
backlight. In your case it doesn't seem to be working. You might try
a newer kernel. I fixed some backlight issues in either 3.6 or 3.7
> The actual resume seems to be working fine. For example I can telnet into
> the resumed system. I think this is just a configuration error in Ubuntu
> for this particular hardware. For example I get exactly the same behavior
> if I switch to the fglrx driver, using the "Additional Drivers" script, and
> then forget to run the "aticonfig --initial" script. So I am confident that
> all I have to do is find the right command to turn the light on.
> I do not know what I am doing, so just tell me what to try.
As I said, normally, it should just work. You can try adjusting the
backlight manually with sysfs.
To check the max brightness:
To set a brightness level:
echo [brightness] | sudo tee - /sys/class/backlight/[driver]/brightness
replace [brightness] with whatever level you want to set and replace
[driver] with the name of the backlight device on your system. You
may have more than one so try all of them. E.g.,
More information about the xorg-driver-ati