Backlight not restored when moving the mouse

Interesting; few people confirm in bug 840683 that the dimming doesn't occur at all. The bug's description and second comment suggest that the 'dim on idle and on power' option isn't even coded or at least its description is misleading. What graphic card do you use? I recommend you to follow that bug report too. Feel free to continue to report any other bugs you may find.

Status changed to 'Confirmed' because the bug affects multiple users.

Sorry for the delay...
I've an Intel graphic card
00:02.0 VGA compatible controller: Intel Corporation Mobile 4 Series Chipset Integrated Graphics Controller (rev 09)
After some other investigation I will try to summarise the problem, because I've seen different behaviour with dim enabled/disabled

With dim enabled:
1)leave pc idle
2)when the monitor goes black wait a few minutes
3)move the mouse/keyboard but the screen remains black, even if you change screen brightness using the special key (Fn-F6)

With dim disabled:
1)leave pc idle
2)when the monitor goes black wait a few minutes
3)move the mouse/keyboard but the screen remains black
4)if you change increase screen brightness using the special key (Fn-F6) the back light turn on and I can use the pc

Note: if I leave the pc idle for about an hour with even with dim disabled I cannot any more restore the back light

Feel free to ask me clarification if my description is not very clear...

Where is the "Dim on idle" option located in Oneiric? I cannot seem to find it...

Ader,
you can find "dim on idle" going to

1)System settings
2)Screen
3)"Dim screen to save power"

I've just changed bug description and title, because I've noticed that the problem is independent from "dim screen to save power"
So the problem is very simple: the backlight is not restored when I move the mouse, but I must manually turn on it.

The problem is present in only one of my laptop, precisely an Asus K50IJ; the graphic card is an Intel "Mobile 4 Series Chipset Integrated Graphics Controller [8086:2A42]"

Adding lightdm because I've discovered another issue:
1)boot Ubuntu
2)leave pc idle without logging in
3)after 10 minutes (as I've set in screen settings) the screen goes standby
4)I cannot restore backlight even using keyboard shortcut (I think because I'm not logged in)
5)I've only one user so the focus is on password field, so I can enter the password although the screen is off
6)As soon the system enter Gnome session I can restore backlight using keyboard shortcut

Is a strange problem...maybe it affects more modules (ligthdm, gnome-power-manager, graphic card driver??...), but I cannot reproduce it on other laptops, does anyone have a tip on how to isolate this bug to help resolving it?

Thanks

Please try to find any related error messages from syslog (should be listed in Log viewer, if not open /var/log/syslog with that program).

Thanks for the tip; here are some errors that appear after the screen goes off (the timeout is 10 minutes)

Oct 25 22:34:10 alessio-laptop udev-configure-printer: Failed to get parent
Oct 25 22:34:26 alessio-laptop dbus[878]: [system] Reloaded configuration
Oct 25 22:35:37 dbus[878]: last message repeated 6 times
Oct 25 22:45:14 alessio-laptop kernel: [ 1893.203921] ACPI Error: Result stack is empty! State=d9859c00 (20110413/dswstate-98)
Oct 25 22:45:14 alessio-laptop kernel: [ 1893.203934] ACPI Exception: AE_AML_NO_RETURN_VALUE, Missing or null operand (20110413/dsutils-646)
Oct 25 22:45:14 alessio-laptop kernel: [ 1893.203942] ACPI Exception: AE_AML_NO_RETURN_VALUE, While creating Arg 1 (20110413/dsutils-763)
Oct 25 22:45:14 alessio-laptop kernel: [ 1893.203951] ACPI Error: Method parse/execution failed [\_SB_.PCI0.VGA_.UPBL] (Node f4428e40), AE_AML_NO_RETURN_VALUE (20110413/psparse-536)
Oct 25 22:45:14 alessio-laptop kernel: [ 1893.203967] ACPI Error: Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_._Q0F] (Node f442d270), AE_AML_NO_RETURN_VALUE (20110413/psparse-536)
Oct 25 22:45:15 alessio-laptop kernel: [ 1893.970634] ACPI Error: Result stack is empty! State=d9858800 (20110413/dswstate-98)
Oct 25 22:45:15 alessio-laptop kernel: [ 1893.970647] ACPI Exception: AE_AML_NO_RETURN_VALUE, Missing or null operand (20110413/dsutils-646)
Oct 25 22:45:15 alessio-laptop kernel: [ 1893.970655] ACPI Exception: AE_AML_NO_RETURN_VALUE, While creating Arg 1 (20110413/dsutils-763)
Oct 25 22:45:15 alessio-laptop kernel: [ 1893.970665] ACPI Error: Method parse/execution failed [\_SB_.PCI0.VGA_.UPBL] (Node f4428e40), AE_AML_NO_RETURN_VALUE (20110413/psparse-536)
Oct 25 22:45:15 alessio-laptop kernel: [ 1893.970680] ACPI Error: Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_._Q0F] (Node f442d270), AE_AML_NO_RETURN_VALUE (20110413/psparse-536)
Oct 25 22:45:15 alessio-laptop kernel: [ 1894.231842] ACPI Error: Result stack is empty! State=d9858800 (20110413/dswstate-98)
Oct 25 22:45:15 alessio-laptop kernel: [ 1894.231854] ACPI Exception: AE_AML_NO_RETURN_VALUE, Missing or null operand (20110413/dsutils-646)
Oct 25 22:45:15 alessio-laptop kernel: [ 1894.231862] ACPI Exception: AE_AML_NO_RETURN_VALUE, While creating Arg 1 (20110413/dsutils-763)
Oct 25 22:45:15 alessio-laptop kernel: [ 1894.231871] ACPI Error: Method parse/execution failed [\_SB_.PCI0.VGA_.UPBL] (Node f4428e40), AE_AML_NO_RETURN_VALUE (20110413/psparse-536)
Oct 25 22:45:15 alessio-laptop kernel: [ 1894.231887] ACPI Error: Method parse/execution failed [\_SB_.PCI0.SBRG.EC0_._Q0F] (Node f442d270), AE_AML_NO_RETURN_VALUE (20110413/psparse-536)
Oct 25 22:45:15 alessio-laptop kernel: [ 1894.269182] ACPI Error: Result stack is empty! State=ed03dc00 (20110413/dswstate-98)
Oct 25 22:45:15 alessio-laptop kernel: [ 1894.269192] ACPI Exception: AE_AML_NO_RETURN_VALUE, Missing or null operand (20110413/dsutils-646)
Oct 25 22:45:15 alessio-laptop kernel: [ 1894.269196] ACPI Exception: AE_AML_NO_RETURN_VALUE, While creating Arg 1 (20110413/dsutils-763)
Oct 25 22:45:15 alessio-laptop kernel: [ 1894.269201] ACPI Error: Method parse/execution failed [\_SB_.PCI0.VGA_.UPBL] (Node f4428e40), AE_AML_NO_RETURN_...

Status changed to 'Confirmed' because the bug affects multiple users.

Thank you for your bug report, that seems like a request to have the g-s-d media key plugin activated on the unity greeter

Sebastien, I'm not very familiar with ACPI, but in the log that I've attached it seems that there is an error on ACPI, do you think we should assign this bug also to ACPI?

Thanks

Status changed to 'Confirmed' because the bug affects multiple users.

I am running Ubuntu 11.10 32 bit on a Lenovo B570 and can confirm this bug.
See the attached screenshot for the settings.

After one minute the display is turned off and neither moving the mouse or pressing keys will reactivate it.
No messages appear in the syslog.

Pressing FN+UP (increase brightness) however does turn on the monitor, setting it to minimum brightness (that is: the first step with actual brightness, not off). If I keep holding down those keys the screen will brighten up to the normal, fully usable level.
When pressing FN+UP the syslog gets flooded with the following messages:

Dec 18 12:41:52 laptop32 kernel: [ 930.178719] ACPI: Failed to switch the brightness
Dec 18 12:41:52 laptop32 kernel: [ 930.251163] ACPI: Failed to switch the brightness
Dec 18 12:41:52 laptop32 kernel: [ 930.323450] ACPI: Failed to switch the brightness
Dec 18 12:41:52 laptop32 kernel: [ 930.676270] ACPI: Failed to switch the brightness
Dec 18 12:41:52 laptop32 kernel: [ 930.889567] ACPI: Failed to switch the brightness
Dec 18 12:41:54 laptop32 kernel: [ 932.370370] ACPI: Failed to switch the brightness
Dec 18 12:41:54 laptop32 kernel: [ 932.565523] ACPI: Failed to switch the brightness
Dec 18 12:41:54 laptop32 kernel: [ 932.750587] ACPI: Failed to switch the brightness
Dec 18 12:41:58 laptop32 kernel: [ 936.317939] ACPI: Failed to switch the brightness

Experiencing almost the same here. After 10 minutes of inactivity, the screen turns off. When moving the mouse, only the cursor is visible. The rest of the screen looks like the backlight is off. When pushing Alt+Ctrl+F1 and then Alt+Ctrl+F7, the brightness is restored. No login screen was displayed. I have the same isue when locking the machine, cursor stays visible, rest not. Typing password+enter restores visibility again.

System;
Ubuntu 11.10 x64
Intel® Core™2 Quad CPU Q9550
ATI Radeon HD 4870 X2 (fglrx 11.12) - one monitor

End of syslog;
Jan 7 12:59:27 dennis-desktop kernel: [ 3241.524210] gnome-screensav[2344]: segfault at 5 ip 00007f1793d39859 sp 00007fff5a342a00 error 4 in libcairo.so.2.11000.2[7f1793d00000+b9000]
Jan 7 12:59:27 dennis-desktop gnome-session[2262]: WARNING: Detected that screensaver has left the bus
Jan 7 13:17:01 dennis-desktop CRON[3886]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly)
Jan 7 13:22:06 dennis-desktop kernel: [ 4600.536160] vgaarb: this pci device is not a vga device
Jan 7 13:59:17 dennis-desktop kernel: [ 6832.000641] vgaarb: this pci device is not a vga device
Jan 7 13:59:18 dennis-desktop kernel: [ 6832.494666] gnome-screensav[3983]: segfault at 5 ip 00007f9c72ab6859 sp 00007fffc0aeb390 error 4 in libcairo.so.2.11000.2[7f9c72a7d000+b9000]
Jan 7 13:59:18 dennis-desktop gnome-session[2262]: WARNING: Detected that screensaver has left the bus
Jan 7 14:16:02 dennis-desktop kernel: [ 7836.126481] vgaarb: this pci device is not a vga device
Jan 7 14:17:01 dennis-desktop CRON[4442]: (root) CMD ( cd / && run-parts --report /etc/cron.hourly)
Jan 7 14:25:49 dennis-desktop kernel: [ 8423.137963] gnome-screensav[4746]: segfault at 5 ip 00007fd3cc610859 sp 00007fff30c4e370 error 4 in libcairo.so.2.11000.2[7fd3cc5d7000+b9000]
Jan 7 14:25:49 dennis-desktop gnome-session[2262]: WARNING: Detected that screensaver has left the bus

I've just noticed that this bug is related to Unity, in fact, if I run gnome shell the issue doesn't occur!

Is the bug related to https://bugs.launchpad.net/ubuntu/+source/linux/+bug/189260 ?

It could be...in fact the behaviour is similar...but I also think is related to Unity, in fact since I switched to Gnome Shell I don't have this problem anymore...

I have a similar problem in 22.04 Thinkpad 430. After coming back from standby is at lowest level and I need to increase by using the special keyboard keys. I did not have it before the upgrade in 18.04.

```
Jun 28 08:59:08 username kernel: [ 4.917544] thinkpad_acpi: This ThinkPad has standard ACPI backlight brightness control, supported by the ACPI video driver
Jun 28 08:59:08 username kernel: [ 5.035849] thinkpad_acpi: Standard ACPI backlight interface available, not loading native one
Jun 29 09:46:20 username kernel: [51863.067875] video LNXVIDEO:00: Restoring backlight state
Jun 29 22:20:29 username kernel: [ 6.814113] thinkpad_acpi: This ThinkPad has standard ACPI backlight brightness control, supported by the ACPI video driver
Jun 29 22:20:29 username kernel: [ 6.894725] thinkpad_acpi: Standard ACPI backlight interface available, not loading native one
Jun 29 22:20:29 username systemd[1]: Created slice Slice /system/systemd-backlight.
Jun 29 22:20:29 username systemd[1]: Starting Load/Save Screen Backlight Brightness of leds:tpacpi::kbd_backlight...
Jun 29 22:20:29 username systemd[1]: Finished Load/Save Screen Backlight Brightness of leds:tpacpi::kbd_backlight.
Jun 29 22:20:29 username systemd[1]: Starting Load/Save Screen Backlight Brightness of backlight:acpi_video0...
Jun 29 22:20:29 username systemd[1]: Starting Load/Save Screen Backlight Brightness of backlight:intel_backlight...
Jun 29 22:20:29 username systemd[1]: Finished Load/Save Screen Backlight Brightness of backlight:intel_backlight.
Jun 29 22:20:29 username systemd[1]: Finished Load/Save Screen Backlight Brightness of backlight:acpi_video0.
Jun 30 08:00:18 username kernel: [ 5430.745580] video LNXVIDEO:00: Restoring backlight state
```