[Asus UX32VD] Backlight controls have no effect after suspend in most recent kernel

[RK]

After recent updates, the backlight doesn't work after suspend on my Asus UX32VD laptop. The hotkeys work as far as the Unity graphical indicator goes, but there is no change in backlight. The hotkeys used to work, and have worked for the last couple of years.

Backlight is restored and does work after restarting, but can no longer be modified after suspend.

This is the output from
ls /sys/class/backlight > backlight
"acpi_video0
acpi_video1
intel_backlight"

This is the output from
grep -r . /proc/acpi > acpi

ProblemType: Bug
DistroRelease: Ubuntu 14.04
Package: linux-image-3.13.0-39-generic 3.13.0-39.66
ProcVersionSignature: Ubuntu 3.13.0-39.66-generic 3.13.11.8
Uname: Linux 3.13.0-39-generic x86_64
ApportVersion: 2.14.1-0ubuntu3.5
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: rasmus 2439 F.... pulseaudio
 /dev/snd/pcmC0D0p: rasmus 2439 F...m pulseaudio
CurrentDesktop: Unity
Date: Wed Nov 12 08:22:20 2014
EcryptfsInUse: Yes
HibernationDevice: RESUME=UUID=49ecb728-6268-4421-9baf-b50a95225410
InstallationDate: Installed on 2012-08-10 (823 days ago)
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Release amd64 (20120425)
MachineType: ASUSTeK COMPUTER INC. UX32VD
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.13.0-39-generic root=UUID=8f94976f-77a4-4e28-a0a8-2e0ce9149ef8 ro quiet splash pcie_aspm=force vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.13.0-39-generic N/A
 linux-backports-modules-3.13.0-39-generic N/A
 linux-firmware 1.127.8
SourcePackage: linux
StagingDrivers: rts5139
UpgradeStatus: Upgraded to trusty on 2014-05-31 (164 days ago)
dmi.bios.date: 06/06/2012
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: UX32VD.206
dmi.board.asset.tag: ATN12345678901234567
dmi.board.name: UX32VD
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: 1.0
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK COMPUTER INC.
dmi.chassis.version: 1.0
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrUX32VD.206:bd06/06/2012:svnASUSTeKCOMPUTERINC.:pnUX32VD:pvr1.0:rvnASUSTeKCOMPUTERINC.:rnUX32VD:rvr1.0:cvnASUSTeKCOMPUTERINC.:ct10:cvr1.0:
dmi.product.name: UX32VD
dmi.product.version: 1.0
dmi.sys.vendor: ASUSTeK COMPUTER INC.

[Brad Figg (brad-figg)]

This change was made by a bot.

[RK (shandolad)]

Output from
$ acpixtract acpidump.txt

Intel ACPI Component Architecture
ACPI Binary Table Extraction Utility version 20140214-64 [Mar 29 2014]
Copyright (c) 2000 - 2014 Intel Corporation

Acpi table [DSDT] - 82426 bytes written to dsdt.dat
Acpi table [SSDT] - 2620 bytes written to ssdt1.dat
Acpi table [SSDT] - 3237 bytes written to ssdt2.dat
Acpi table [SSDT] - 152 bytes written to ssdt3.dat
Acpi table [SSDT] - 2332 bytes written to ssdt4.dat
Acpi table [SSDT] - 2512 bytes written to ssdt5.dat
Acpi table [SSDT] - 2706 bytes written to ssdt6.dat
Acpi table [SSDT] - 2131 bytes written to ssdt7.dat
Acpi table [SSDT] - 771 bytes written to ssdt8.dat
Acpi table [SSDT] - 281 bytes written to ssdt9.dat

[RK (shandolad)]

iasl -d dsdt.dat

Intel ACPI Component Architecture
ASL Optimizing Compiler version 20140214-64 [Mar 29 2014]
Copyright (c) 2000 - 2014 Intel Corporation

Loading Acpi table from file dsdt.dat - Length 00082426 (0141FA)
Acpi table [DSDT] successfully installed and loaded
Pass 1 parse of [DSDT]
Pass 2 parse of [DSDT]
Parsing Deferred Opcodes (Methods/Buffers/Packages/Regions)

Parsing completed

Found 2 external control methods, reparsing with new information
Pass 1 parse of [DSDT]
Pass 2 parse of [DSDT]
Parsing Deferred Opcodes (Methods/Buffers/Packages/Regions)

Parsing completed
Disassembly completed
ASL Output: dsdt.dsl - 707929 bytes

iASL Warning: There were 2 external control methods found during
disassembly, but additional ACPI tables to resolve these externals
were not specified. The resulting disassembler output file may not
compile because the disassembler did not know how many arguments
to assign to these methods. To specify the tables needed to resolve
external control method references, the -e option can be used to
specify the filenames. Example iASL invocations:
    iasl -e ssdt1.aml ssdt2.aml ssdt3.aml -d dsdt.aml
    iasl -e dsdt.aml ssdt2.aml -d ssdt1.aml
    iasl -e ssdt*.aml -d dsdt.aml

In addition, the -fe option can be used to specify a file containing
control method external declarations with the associated method
argument counts. Each line of the file must be of the form:
    External (<method pathname>, MethodObj, <argument count>)

[penalvch (penalvch)]

RK, thank you for reporting this and helping make Ubuntu better. As per http://www.asus.com/us/Notebooks_Ultrabooks/ASUS_ZENBOOK_UX32VD/HelpDesk_Download/ an update to your BIOS is available (214). If you update to this following https://help.ubuntu.com/community/BIOSUpdate does it change anything? If it doesn't, could you please both specify what happened, and provide the output of the following terminal command:
sudo dmidecode -s bios-version && sudo dmidecode -s bios-release-date

For more on BIOS updates and linux, please see https://help.ubuntu.com/community/ReportingBugs#Bug_reporting_etiquette .

Please note your current BIOS is already in the Bug Description, so posting this on the old BIOS would not be helpful. As well, you don't have to create a new bug report.

Once the BIOS is updated, then please mark this report Status Confirmed.

Thank you for your understanding.

[RK (shandolad)]

Hi,

After updating the BIOS, the backlight control works once more. In fact, I can now also turn off the backlight completely with the same controls, which was not possible before. Furthermore, the backlight control is more fine-grained than before.

It seems that the problem is fixed.

Thanks.

[RK (shandolad)]

(I marked the report as confirmed as per the instructions, even though the problem seems to be solved).

[penalvch (penalvch)]

RK, this bug report is being closed due to your last comment https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1391758/comments/20 regarding this being fixed with a BIOS update. For future reference you can manage the status of your own bugs by clicking on the current status in the yellow line and then choosing a new status in the revealed drop down box. You can learn more about bug statuses at https://wiki.ubuntu.com/Bugs/Status. Thank you again for taking the time to report this bug and helping to make Ubuntu better. Please submit any future bugs you may find.