I own Dell Inspiron M5110 (Q15R). This laptop has no keyboard backlight, but dell-laptop claims otherwise.
My syslog was getting spammed with "Keyboard brightness level control not supported" as dell-laptop was trying to get/set backlight values.
In dell-laptop there is kbd_led_present variable, but on my M5110 it's being set to true:
ret = kbd_init_info();
(...)
if (kbd_token_bits != 0 || ret == 0)
kbd_led_present = true;
kbd_token_bits is 0, but so is ret.
kbd_init_info method is only returning != 0 if kbd_get_info is returning != 0
(Basing on this: http://linux.dell.com/cgi-bin/cgit.cgi/libsmbios.git/tree/src/bin/smbios-keyboard-ctl#n667)
kbd_get_info method returns only cbRES1 value of following smbios call :
cbClass 4
cbSelect 11
cbArg1 0x0
And it returns 0...
I found that any cbRES of this call is giving me nothing but zeros, as if it wasn't defined in my BIOS. I have it's newest version for my laptop:
[ 0.000000] SMBIOS 2.7 present.
[ 0.000000] DMI: Dell Inc. Inspiron M5110/0X7W03, BIOS A05 03/22/2012
However, if "cbRES3, byte2 Number of keyboard light brightness levels" is 0 as well, that should mean backlight is not available, right? I'm attaching possible fix.
This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:
apport-collect 1478696
and then change the status of the bug to 'Confirmed'.
If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.
This change has been made by an automated script, maintained by the Ubuntu Kernel Team.