Bug 41952 - HP Mini 5103, Backlight only on if charger plugged in at kernel boot time
HP Mini 5103, Backlight only on if charger plugged in at kernel boot time
Status: CLOSED INSUFFICIENT_DATA
Product: ACPI
Classification: Unclassified
Component: Power-Video
All Linux
: P1 normal
Assigned To: Aaron Lu
:
Depends on:
Blocks:
  Show dependency treegraph
 
Reported: 2011-08-29 12:12 UTC by D Brown
Modified: 2013-03-28 08:15 UTC (History)
2 users (show)

See Also:
Kernel Version: 3.0
Tree: Mainline
Regression: No


Attachments
acpidump with backlight off (565.63 KB, text/plain)
2011-08-29 12:13 UTC, D Brown
Details
acpidump with backlight on (565.63 KB, text/plain)
2011-08-29 12:20 UTC, D Brown
Details

Description D Brown 2011-08-29 12:12:18 UTC
Hello,

I have an issue with my HP Mini 5103, where the backlight will only be on if the adaptor/charger is plugged in before the kernel boots.
Pulling out/plugging in the charger in grub(0.97 legacy) will either turn off/on the backlight, up until selecting my distribution to boot into (kernel 3.0-ARCH).
Once I have booted (with the backlight on), I can take out the charger and the backlight will remain on.
If I boot without the charger plugged in and then plug in the charger during running linux, the backlight will still remain off.
With the both the backlight on and off, I have tried changing the values of bl_power (in /sys/class/backlight/acpi_video0 - symlinked to /sys/devices/pci0000:00/0000:00:02.0/backlight/acpi_video0) from 0 to 5 (-1 didn't work), with no change in backlight power (although the change in value was registered), even rebooting to test the change with no luck.
The value of bl_power with both backlight on and off is 0.
I have tried this both in virtual console and in a basic x setup with no change in backlight power.
All other functions of changing the brightness both with Fn Keys and manually echoing into brightness (max_brightness=24) work fine.
I have laptop-mode installed and running, although the backlight issue always happens regardless of whether or not it is running.
I remember this always happening when I used to run Ubuntu 11.04 March-May (can't remember kernel version sorry), and the backlight is always on/works fine in Windows 7.
Thanks for your time and for already making everything else work great. If you need any more info I will gladly help.


$:ls -lH /sys/class/backlight/acpi_video0
total 0
-r--r--r-- 1 root root 4096 Aug 29 20:53 actual_brightness
-rw-r--r-- 1 root root 4096 Aug 29 23:33 bl_power
-rw-r--r-- 1 root root 4096 Aug 29 20:53 brightness
lrwxrwxrwx 1 root root    0 Aug 29 23:20 device -> ../../../0000:00:02.0/
-r--r--r-- 1 root root 4096 Aug 29 20:53 max_brightness
drwxr-xr-x 2 root root    0 Aug 29 20:53 power/
lrwxrwxrwx 1 root root    0 Aug 29 20:40 subsystem -> ../../../../../class/backlight/
-r--r--r-- 1 root root 4096 Aug 29 20:53 type
-rw-r--r-- 1 root root 4096 Aug 29 20:40 uevent

$:lspci
00:00.0 Host bridge: Intel Corporation N10 Family DMI Bridge
00:02.0 VGA compatible controller: Intel Corporation N10 Family Integrated Graphics Controller
00:02.1 Display controller: Intel Corporation N10 Family Integrated Graphics Controller
00:1b.0 Audio device: Intel Corporation N10/ICH 7 Family High Definition Audio Controller (rev 02)
00:1c.0 PCI bridge: Intel Corporation N10/ICH 7 Family PCI Express Port 1 (rev 02)
00:1c.3 PCI bridge: Intel Corporation N10/ICH 7 Family PCI Express Port 4 (rev 02)
00:1d.0 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #1 (rev 02)
00:1d.1 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #2 (rev 02)
00:1d.2 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #3 (rev 02)
00:1d.3 USB Controller: Intel Corporation N10/ICH 7 Family USB UHCI Controller #4 (rev 02)
00:1d.7 USB Controller: Intel Corporation N10/ICH 7 Family USB2 EHCI Controller (rev 02)
00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e2)
00:1f.0 ISA bridge: Intel Corporation NM10 Family LPC Controller (rev 02)
00:1f.2 SATA controller: Intel Corporation N10/ICH7 Family SATA AHCI Controller (rev 02)
01:00.0 Network controller: Broadcom Corporation BCM43224 802.11a/b/g/n (rev 01)


Specific mentions of error with regards to the HP Mini 5103
http://ubuntuforums.org/showthread.php?t=1749326
http://www.linlap.com/wiki/hp+mini+5103

Other mentions of backlight error
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/772050
https://bugzilla.kernel.org/show_bug.cgi?id=37282
Comment 1 D Brown 2011-08-29 12:13:56 UTC
Created attachment 70772 [details]
acpidump with backlight off
Comment 2 D Brown 2011-08-29 12:20:35 UTC
Created attachment 70782 [details]
acpidump with backlight on
Comment 3 D Brown 2011-09-06 10:08:53 UTC
I can confirm that if the backlight is on when hibernated (pm-hibernate), the backlight will remain on once resumed.  What other information would you like me to provide/test?
Cheers
Comment 4 Zhang Rui 2012-11-13 08:40:48 UTC
(In reply to comment #0)
> Hello,
> 
> I have an issue with my HP Mini 5103, where the backlight will only be on if
> the adaptor/charger is plugged in before the kernel boots.
> Pulling out/plugging in the charger in grub(0.97 legacy) will either turn
> off/on the backlight, up until selecting my distribution to boot into (kernel
> 3.0-ARCH).
> Once I have booted (with the backlight on), I can take out the charger and the
> backlight will remain on.
> If I boot without the charger plugged in and then plug in the charger during
> running linux, the backlight will still remain off.
> With the both the backlight on and off, I have tried changing the values of
> bl_power (in /sys/class/backlight/acpi_video0 - symlinked to
> /sys/devices/pci0000:00/0000:00:02.0/backlight/acpi_video0) from 0 to 5 (-1
> didn't work), with no change in backlight power (although the change in value
> was registered), even rebooting to test the change with no luck.

do you mean poking /sys/class/backlight/acpi_video0/actual_brightness can not change the actual backlight?

> The value of bl_power with both backlight on and off is 0.
> I have tried this both in virtual console and in a basic x setup with no change
> in backlight power.
> All other functions of changing the brightness both with Fn Keys and manually
> echoing into brightness (max_brightness=24) work fine.

what does "manually echoing into brightness" mean?

please attach the output of "grep . /sys/class/backlight/*/*"
Comment 5 Zhang Rui 2012-11-28 07:21:01 UTC
ping...
Comment 6 Zhang Rui 2012-12-11 01:43:34 UTC
ping...
Comment 7 Aaron Lu 2013-03-15 07:36:32 UTC
Hi Brown,

Are you still there?

So your problem is, when you starts the computer without plugging the charger, the screen will be off, and all the way off even after you start Linux, right? The backlight on/off may be controlled by graphics drm driver, but I'm not sure about that. And the fact that before OS starts, the backlight is also off sounds like a BIOS/hardware issue to me.

BTW, bl_power isn't implemented for acpi_video sysfs interface, so it won't turn on/off the backlight.

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