Public bug reported:
Fn-shortcuts work and the value in
/sys/class/backlight/intel_backlight/brightness changes, but is has no physical
effect.
Only setting /sys/class/backlight/intel_backlight/brightness to 0 turns the LCD
off, changing it to any other value turns it on again.
I tried to set different boot parameters in /etc/defaults/grub
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video.use_native_backlight=1"
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video.use_native_backlight=0"
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux acpi_backlight=vendor"
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash video.use_bios_initial_backlight=0"
For each change, I called update-grub, restarted, and verfied the
settings with /proc/cmdline. Nothing worked for me.
I also tested this with the newest mainline kernel (4.1-rc2), but the
bug still exists.
It work with trusty and stopped working with utopic. I thought this
issue would may be fixed in vivid, but it isn't.
Please tell me what other information you need in order to fix this.
ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: linux-image-3.19.0-16-generic 3.19.0-16.16
ProcVersionSignature: Ubuntu 3.19.0-16.16-generic 3.19.3
Uname: Linux 3.19.0-16-generic x86_64
ApportVersion: 2.17.2-0ubuntu1
Architecture: amd64
AudioDevicesInUse:
USER PID ACCESS COMMAND
/dev/snd/controlC0: stefan 1383 F.... pulseaudio
CurrentDesktop: KDE
Date: Tue May 12 13:08:51 2015
HibernationDevice: RESUME=UUID=34e06653-f31c-45ef-80ca-9eddcae5134f
InstallationDate: Installed on 2015-03-10 (62 days ago)
InstallationMedia: Kubuntu-Plasma-5 14.10 "Utopic Unicorn" - Release amd64
(20141022)
MachineType: SAMSUNG ELECTRONICS CO., LTD. 730U3E/740U3E
ProcFB:
0 inteldrmfb
1 radeondrmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-3.19.0-16-generic
root=/dev/mapper/kubuntu--plasma--5--vg-root ro quiet splash
video.use_bios_initial_backlight=0
RelatedPackageVersions:
linux-restricted-modules-3.19.0-16-generic N/A
linux-backports-modules-3.19.0-16-generic N/A
linux-firmware 1.143
SourcePackage: linux
UpgradeStatus: Upgraded to vivid on 2015-04-26 (16 days ago)
dmi.bios.date: 05/30/2013
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: P05ABW.060.130530.dg
dmi.board.asset.tag: No Asset Tag
dmi.board.name: NP730U3E-S03DE
dmi.board.vendor: SAMSUNG ELECTRONICS CO., LTD.
dmi.board.version: SEC_SW_REVISION_1234567890ABCD
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 9
dmi.chassis.vendor: SAMSUNG ELECTRONICS CO., LTD.
dmi.chassis.version: N/A
dmi.modalias:
dmi:bvnAmericanMegatrendsInc.:bvrP05ABW.060.130530.dg:bd05/30/2013:svnSAMSUNGELECTRONICSCO.,LTD.:pn730U3E/740U3E:pvrP05ABW:rvnSAMSUNGELECTRONICSCO.,LTD.:rnNP730U3E-S03DE:rvrSEC_SW_REVISION_1234567890ABCD:cvnSAMSUNGELECTRONICSCO.,LTD.:ct9:cvrN/A:
dmi.product.name: 730U3E/740U3E
dmi.product.version: P05ABW
dmi.sys.vendor: SAMSUNG ELECTRONICS CO., LTD.
** Affects: linux (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug vivid
** Summary changed:
- LCD backlight brightness control doesn't work
+ Samsung 730U3E LCD backlight brightness control doesn't work
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https://bugs.launchpad.net/bugs/1454207
Title:
Samsung 730U3E LCD backlight brightness control doesn't work
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