intel graphics rc6 power saving causes flickering

[Giampiero Salvi]

Since RC6 power saving was enabled by default, disconnecting the power cable causes flickering in the screen.

WORKAROUND: Disable RC6 power saving by adding "i915.i915_enable_rc6=0" to the GRUB_CMDLINE_LINUX_DEFAULT variable in /etc/default/grub and by running:
sudo update-grub

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: linux-image-3.2.0-29-generic-pae 3.2.0-29.46
ProcVersionSignature: Ubuntu 3.2.0-29.46-generic-pae 3.2.24
Uname: Linux 3.2.0-29-generic-pae i686
AlsaVersion: Advanced Linux Sound Architecture Driver Version 1.0.24.
AplayDevices:
 **** List of PLAYBACK Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC269VB Analog [ALC269VB Analog]
   Subdevices: 0/1
   Subdevice #0: subdevice #0
ApportVersion: 2.0.1-0ubuntu12
Architecture: i386
ArecordDevices:
 **** List of CAPTURE Hardware Devices ****
 card 0: Intel [HDA Intel], device 0: ALC269VB Analog [ALC269VB Analog]
   Subdevices: 1/1
   Subdevice #0: subdevice #0
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: giampi 1689 F.... pulseaudio
 /dev/snd/pcmC0D0p: giampi 1689 F...m pulseaudio
Card0.Amixer.info:
 Card hw:0 'Intel'/'HDA Intel at 0xf7cf8000 irq 45'
   Mixer name : 'Realtek ALC269VB'
   Components : 'HDA:10ec0269,10438437,00100100'
   Controls : 13
   Simple ctrls : 8
Date: Tue Aug 28 09:41:13 2012
HibernationDevice: RESUME=UUID=70fefe68-bbe7-4083-9663-fd32cdb604dc
InstallationMedia: Ubuntu-Netbook 10.10 "Maverick Meerkat" - Release i386 (20101007)
MachineType: ASUSTeK Computer INC. 1001PX
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-29-generic-pae root=UUID=a36ef87b-13ea-4ce2-bac3-ebf4d415e6ef ro quiet splash i915.i915_enable_rc6=0 vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.2.0-29-generic-pae N/A
 linux-backports-modules-3.2.0-29-generic-pae N/A
 linux-firmware 1.79
SourcePackage: linux
UpgradeStatus: Upgraded to precise on 2012-05-05 (114 days ago)
dmi.bios.date: 08/12/2010
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 0904
dmi.board.asset.tag: To Be Filled By O.E.M.
dmi.board.name: 1001PX
dmi.board.vendor: ASUSTeK Computer INC.
dmi.board.version: x.xx
dmi.chassis.asset.tag: 0x00000000
dmi.chassis.type: 10
dmi.chassis.vendor: ASUSTeK Computer INC.
dmi.chassis.version: x.x
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr0904:bd08/12/2010:svnASUSTeKComputerINC.:pn1001PX:pvrx.x:rvnASUSTeKComputerINC.:rn1001PX:rvrx.xx:cvnASUSTeKComputerINC.:ct10:cvrx.x:
dmi.product.name: 1001PX
dmi.product.version: x.x
dmi.sys.vendor: ASUSTeK Computer INC.

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.6 kernel[0] (Not a kernel in the daily directory) and install both the linux-image and linux-image-extra .deb packages.

Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag. Please only remove that one tag and leave the other tags. This can be done by clicking on the yellow pencil icon next to the tag located at the bottom of the bug description and deleting the 'needs-upstream-testing' text.

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.6-rc3-quantal/

[Giampiero Salvi (giampisalvi)]

Hi,
I followed the link at http://kernel.ubuntu.com/~kernel-ppa/mainline/ and the only builds for versions v3.6 I can find are for "quantal" (rc1, rc2 and rc3). Is that right? I am running "precise" on the netbook, does it mean it is possible to take a kernel from another release of Ubuntu? Or am I looking in the wrong place?

Thank you,
Giampiero

[Giampiero Salvi (giampisalvi)]

Sorry for the last message, I now see that you explicitly pointed to the quantal kernel, so I assume it is ok to use it.

Giampiero

[Giampiero Salvi (giampisalvi)]

Hi,
I have now tested the upstream kernel by removing the 'i915.i915_enable_rc6=0' kernel option and installing 3.6.0-030600rc3-generic. I could not observe any flickering when the power cable is disconnected, so I marked the bug the way you told me to do.

Is there any chance this will be fixed in 'precise' as well?

Thank you for your help!
Giampiero

[Joseph Salisbury (jsalisbury)]

@Giampiero,

We would need to perform a "Reverse" bisect to identify the commit that fixes this bug in v3.6-rc3. Would it be possible for you to test some kernels if I perform a reverse bisect?

[Giampiero Salvi (giampisalvi)]

@Joseph,

Do you have a standard procedure for that? Or shall I just take a kernel in between 3.2.0 and 3.6.0 and keep on splitting between the working and the not-working kernel version?

[Giampiero Salvi (giampisalvi)]

Another question: is there a way to make sure that RC6 is on? When I checked the estimated battery time, I didn't see any difference between kernel 3.2.0 with RC6 disabled in grub, and kernel 3.6.0 with RC6 presumably on (by default). I want to avoid testing a lot of kernels and then realizing that the reason for them to work is that RC6 was disabled for some reason.

[Giampiero Salvi (giampisalvi)]

Hi again,
after testing with a few kernels, I realized that 3.6.0-030600rc3-generic (the latest kernel) does not really solve the problem, it just makes it slightly less serious. I'll try to explain:

Sometimes the flickering happens as soon as I disconnect the power cable, sometimes only when, running on battery, I move the screen of the laptop, which made me originally think it was a wiring problem. But:

1) running on power I can never get the flickering even if I move the screen around
2) most of kernels I tested start flickering as soon as I disconnect the cable
3) when the flickering starts there is usually no way to stop it but to reconnect the power
4) with 3.6.0 rc3 it seems that I can get the flickering by moving the screen but that the problem stops after some time I stop moving it

The behavior in 4) may just be random, but I tested a few times and it seems consistent. I guess I'll change the tags back.

Here are the kernels I tested:
config-3.2.0-29-generic-pae fail
3.4.0-030400-generic fail
3.5.0-030500-generic fail
3.5.3-030503-generic fail
3.6.0-030600rc2-generic fail
3.6.0-030600rc3-generic mostly fail

[Giampiero Salvi (giampisalvi)]

After more testing, I can confirm that the latest kernel (3.6.0 rc3) behaves similarly to the previous ones. That is, the problem persists.

[Joseph Salisbury (jsalisbury)]

This issue appears to be an upstream bug, since you tested the latest upstream kernel. Would it be possible for you to open an upstream bug report[0]? That will allow the upstream Developers to examine the issue, and may provide a quicker resolution to the bug.

If you are comfortable with opening a bug upstream, It would be great if you can report back the upstream bug number in this bug report. That will allow us to link this bug to the upstream report.

[0] https://wiki.ubuntu.com/Bugs/Upstream/kernel

[Giampiero Salvi (giampisalvi)]

Hi Daniel,
I hope you are the right person to contact about this upstream bug.
I'll try to follow the form at
https://wiki.ubuntu.com/Bugs/Upstream/kernel to report it. Please
consider that it's the first time I report an upstream bug :)

Best,
Giampiero

[1.] One line summary of the problem:

intel graphics rc6 power saving causes flickering

[2.] Full description of the problem/report:

Since RC6 power saving was enabled by default (Ubuntu 12.04),
disconnecting the power cable causes flickering in the screen. The
problem is solved by disabling RC6 power saving in the kernel
parameters. This is done by adding "i915.i915_enable_rc6=0" to the
GRUB_CMDLINE_LINUX_DEFAULT variable in /etc/default/grub and by
running 'sudo update-grub'.

The problem seems to be related to the power level that the video card
sends to the screen, that seems to become comparable to the thermal
noise and makes the screen loose sync. In fact, in a minority of
times, I need to move the screen back and forward to trigger the
problem, which made me think of a wiring problem in the beginning.
However, the problem never occurs when I am connected to the power
source even when I move the screen strongly.

[3.] Keywords (i.e., modules, networking, kernel):

kernel, modules, intel graphics, flickering

[4.] Kernel version (from /proc/version):

Linux version 3.6.0-030600rc3-generic (apw@gomeisa) (gcc version 4.6.3
(Ubuntu/Linaro 4.6.3-1ubuntu5) ) #201208221735 SMP Wed Aug 22 21:45:31
UTC 2012

[5.] Output of Oops.. message (if applicable) with symbolic
information resolved (see Documentation/oops-tracing.txt)

does not apply

[6.] A small shell script or example program which triggers the
problem (if possible)

a script is not needed to trigger the problem

[7.] Environment

Description: Ubuntu 12.04.1 LTS
Release: 12.04

[7.1.] Software (add the output of the ver_linux script here)

If some fields are empty or look unusual you may have an old version.
Compare to the current minimal requirements in Documentation/Changes.

Linux ctt-netbook 3.6.0-030600rc3-generic #201208221735 SMP Wed Aug 22
21:45:31 UTC 2012 i686 i686 i386 GNU/Linux

Gnu C 4.6
Gnu make 3.81
binutils 2.22
util-linux 2.20.1
mount support
module-init-tools 3.16
e2fsprogs 1.42
pcmciautils 018
Linux C Library 2.15
Dynamic linker (ldd) 2.15
Procps 3.2.8
Net-tools 1.60
Kbd 1.15.2
Sh-utils 8.13
wireless-tools 30
Modules Loaded rfcomm bnep bluetooth parport_pc ppdev
binfmt_misc dm_crypt joydev arc4 snd_hda_codec_realtek snd_hda_intel
snd_hda_codec ath9k mac80211 eeepc_wmi asus_wmi snd_hwdep snd_pcm
coretemp snd_seq_midi ath9k_common ath9k_hw sparse_keymap snd_rawmidi
snd_seq_midi_event snd_seq ath microcode snd_timer psmouse
snd_seq_device snd serio_raw cfg80211 soundcore snd_page_alloc lpc_ich
mac_hid lp parport i915 atl1c drm_kms_helper drm i2c_algo_bit video
wmi

[7.2.] Processor information (from /proc/cpuinfo):

processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 28
model name : Intel(R) Atom(TM) CPU N450 @ 1.66GH...

[Giampiero Salvi (giampisalvi)]

Hi,
I did as you said: wrote to Daniel Vetter with cc to <email address hidden>, but I got this error message from launchpad:

An error occurred while processing a mail you sent to Launchpad's email
interface.

and then a long list of commands that failed. I don't know if it's important

[Daniel Vetter (daniel-vetter)]

On Wed, Aug 29, 2012 at 7:15 PM, Giampiero Salvi <email address hidden> wrote:
> Hi Daniel,
> I hope you are the right person to contact about this upstream bug.
> I'll try to follow the form at
> https://wiki.ubuntu.com/Bugs/Upstream/kernel to report it. Please
> consider that it's the first time I report an upstream bug :)

Bug report looks good, but mailing your maintainer won't scale. Please
file at bugs.freedesktop.org against dri -> drm/intel. You can pretty
much ditch all the additional information, save for maybe an lspci -nn
attachment.

Also, retesting on latest 3.6-rc3 kernels would be rather interesting,
we've fixed a few things that /might/ apply to your issue.

Yours, Daniel

>
> Best,
> Giampiero
>
> [1.] One line summary of the problem:
>
> intel graphics rc6 power saving causes flickering
>
> [2.] Full description of the problem/report:
>
> Since RC6 power saving was enabled by default (Ubuntu 12.04),
> disconnecting the power cable causes flickering in the screen. The
> problem is solved by disabling RC6 power saving in the kernel
> parameters. This is done by adding "i915.i915_enable_rc6=0" to the
> GRUB_CMDLINE_LINUX_DEFAULT variable in /etc/default/grub and by
> running 'sudo update-grub'.
>
> The problem seems to be related to the power level that the video card
> sends to the screen, that seems to become comparable to the thermal
> noise and makes the screen loose sync. In fact, in a minority of
> times, I need to move the screen back and forward to trigger the
> problem, which made me think of a wiring problem in the beginning.
> However, the problem never occurs when I am connected to the power
> source even when I move the screen strongly.
>
> [3.] Keywords (i.e., modules, networking, kernel):
>
> kernel, modules, intel graphics, flickering
>
> [4.] Kernel version (from /proc/version):
>
> Linux version 3.6.0-030600rc3-generic (apw@gomeisa) (gcc version 4.6.3
> (Ubuntu/Linaro 4.6.3-1ubuntu5) ) #201208221735 SMP Wed Aug 22 21:45:31
> UTC 2012
>
> [5.] Output of Oops.. message (if applicable) with symbolic
> information resolved (see Documentation/oops-tracing.txt)
>
> does not apply
>
> [6.] A small shell script or example program which triggers the
> problem (if possible)
>
> a script is not needed to trigger the problem
>
> [7.] Environment
>
> Description: Ubuntu 12.04.1 LTS
> Release: 12.04
>
> [7.1.] Software (add the output of the ver_linux script here)
>
> If some fields are empty or look unusual you may have an old version.
> Compare to the current minimal requirements in Documentation/Changes.
>
> Linux ctt-netbook 3.6.0-030600rc3-generic #201208221735 SMP Wed Aug 22
> 21:45:31 UTC 2012 i686 i686 i386 GNU/Linux
>
> Gnu C 4.6
> Gnu make 3.81
> binutils 2.22
> util-linux 2.20.1
> mount support
> module-init-tools 3.16
> e2fsprogs 1.42
> pcmciautils 018
> Linux C Library 2.15
> Dynamic linker (ldd) 2.15
> Procps 3.2.8
> Net-tools 1.60
> Kbd 1.15.2
> Sh-utils 8.13
> wireless-tools 30
> Modules Loaded rfcomm bnep blu...

[penalvch (penalvch)]

Giampiero Salvi, as per http://www.asus.com/Notebooks_Ultrabooks/Eee_PC_1001PX_Seashell/#support an update is available for your BIOS (1201). If you update to this following https://help.ubuntu.com/community/BiosUpdate , does it change anything?

If not, 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

Please note your current BIOS is already in the Bug Description, so posting this on the old BIOS would not be helpful.

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

Thank you for your understanding.

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]