Hello, On 2011-11-09 at 19:55 -0500, Taylor Hedberg wrote:
This is a Dell Latitude D620 laptop with the following graphics-related lines in the lspci output:
00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller (rev 03) 00:02.1 Display controller: Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller (rev 03)
I have a Dell Latitude D420 with the same card.
Since the kernel update, the backlight still blinks off momentarily, but when it comes back on, the screen remains blank. Rather than seeing the rest of the boot messages, the display is just black (but backlit). The system still seems to boot like normal; I boot to the virtual console rather than starting X automatically, and once the hard disk activity stops after booting, I can blindly type my login credentials and issue shell commands, though I still can't see any output.
I do not have this problem, however this sounds familiar:
If I shut the laptop lid, the backlight usually shuts off, and comes back on when I reopen it. However, after the kernel update, around 80% of the time, the backlight seemed to come back on at about a third of its usual brightness. I had to close and reopen it several times, and eventually it would come on at full power like normal.
My display comes back with the minimal brightness setting. Also the XF86MonBrightnessUp (Fn+Up) and XF86MonBrightnessDown (Fn+Down) buttons stopped working. I can restore the previous brightness level and the buttons by running: cat /sys/class/backlight/intel_backlight/max_brightness \ > /sys/class/backlight/intel_backlight/brightness The bug can easily triggered in X by running: xset dpms force off
After downgrading, all of these problems seem to have disappeared.
I haven't bothered to downgrade the kernel yet.
I've scanned through dmesg output and I don't really see anything out of the ordinary. But I admit that I don't really know what I'm looking for. Any thoughts or suggestions?
I found this I my dmesg output: [Firmware Bug]: Duplicate ACPI video bus devices for the same VGA controller, please try module parameter "video.allow_duplicates=1"if the current driver doesn't work. But I also haven't tried this, as the incorrect brightness has not annoyed me enough, yet. Regards, Sebastian