Connecting to network causes screen flickering

doginpants · 2017-05-16 16:50:19

I am having a strange screen flickering issue whenever I connect to a wireless network. In the past I had this issue and set kernel parameters i915 psr and Rc6 = 0, this seemed to fix the issue along with properly configuring the Intel drivers. But the issue seems to have come back. The machine is a MacBook pro 12,1 with intel iris for graphics and broadcom BCM43602 using the brcmfmac module. If its relevant, I am using i3wm. Thanks for any help!

20-intel.conf wrote:

Section "Device"
Identifier "Intel Graphics"
Driver "intel"
#Option "AccelMethod" "sna"
Option "TearFree" "True"
Option "DRI" "3"
EndSection

Last edited by doginpants (2017-05-16 16:53:36)

x33a · 2017-05-16 18:19:35

Does it happen with any network? 2.4 GHz vs 5 GHz? Also, post your journalctl output along with the time it last happened.

doginpants · 2017-05-17 20:35:00

I am not sure that the error occurs with both 2.4 & 5ghz networks as I don't have a 5ghz network to test with. The current network I am on is 2.4ghz. The flickering seems to correspond with network usage, so the more Tx/Rx the more flicker.

Here is output while downloading android studio.

May 17 15:11:34 noahcs rtkit-daemon[5339]: Successfully made thread 5337 of process 5337 (/usr/bin/pulseaudio) owned by '1000' high priority at nice level -11.
May 17 15:11:34 noahcs rtkit-daemon[5339]: Supervising 1 threads of 1 processes of 1 users.
May 17 15:11:34 noahcs rtkit-daemon[5339]: Watchdog thread running.
May 17 15:11:34 noahcs systemd[4506]: Started D-Bus User Message Bus.
May 17 15:11:35 noahcs rtkit-daemon[5339]: Supervising 1 threads of 1 processes of 1 users.
May 17 15:11:35 noahcs rtkit-daemon[5339]: Successfully made thread 5345 of process 5337 (/usr/bin/pulseaudio) owned by '1000' RT at priority 5.
May 17 15:11:35 noahcs rtkit-daemon[5339]: Supervising 2 threads of 1 processes of 1 users.
May 17 15:11:35 noahcs dbus[433]: [system] Activating via systemd: service name='org.bluez' unit='dbus-org.bluez.service'
May 17 15:11:35 noahcs dbus[433]: [system] Activation via systemd failed for unit 'dbus-org.bluez.service': Unit dbus-org.bluez.service not found.
May 17 15:11:35 noahcs systemd[4506]: Started Sound Service.
May 17 15:11:35 noahcs pulseaudio[5337]: E: [pulseaudio] bluez5-util.c: GetManagedObjects() failed: org.freedesktop.systemd1.NoSuchUnit: Unit dbus-org.bluez.service not found.
May 17 15:15:49 noahcs sudo[6018]: noah : TTY=pts/2 ; PWD=/home/noah ; USER=root ; COMMAND=/usr/bin/iw wlp3s0 scan
May 17 15:15:49 noahcs sudo[6018]: pam_unix(sudo:session): session opened for user root by (uid=0)
May 17 15:15:51 noahcs sudo[6018]: pam_unix(sudo:session): session closed for user root
May 17 15:19:37 noahcs sudo[6115]: noah : TTY=pts/2 ; PWD=/home/noah ; USER=root ; COMMAND=/usr/bin/pacman -Syu
May 17 15:19:37 noahcs sudo[6115]: pam_unix(sudo:session): session opened for user root by (uid=0)
May 17 15:19:43 noahcs sudo[6115]: pam_unix(sudo:session): session closed for user root
May 17 15:19:50 noahcs sudo[6197]: noah : TTY=pts/2 ; PWD=/home/noah ; USER=root ; COMMAND=list /usr/bin/pacman --color auto -Sy
May 17 15:19:50 noahcs sudo[6198]: noah : TTY=pts/2 ; PWD=/home/noah ; USER=root ; COMMAND=/usr/bin/pacman --color auto -Sy
May 17 15:19:50 noahcs sudo[6198]: pam_unix(sudo:session): session opened for user root by (uid=0)
May 17 15:19:54 noahcs sudo[6198]: pam_unix(sudo:session): session closed for user root
May 17 15:20:10 noahcs sudo[6320]: noah : TTY=pts/2 ; PWD=/home/noah ; USER=root ; COMMAND=list /usr/bin/pacman --color auto -S android
May 17 15:20:10 noahcs sudo[6321]: noah : TTY=pts/2 ; PWD=/home/noah ; USER=root ; COMMAND=/usr/bin/pacman --color auto -S android
May 17 15:20:10 noahcs sudo[6321]: pam_unix(sudo:session): session opened for user root by (uid=0)
May 17 15:20:10 noahcs sudo[6321]: pam_unix(sudo:session): session closed for user root

x33a · 2017-05-18 05:42:33

Does it only happen on heavy network usage? Can you run a CPU and memory stress test and see if it triggers the behaviour as well?

doginpants · 2017-05-19 05:22:04

Doing the command stress --cpu 4 -m 4 results in no flickering, but the moment I opened pacman update the flickering appeared.

Last edited by doginpants (2017-05-19 05:35:40)

seth · 2017-05-19 06:14:22

sudo iwconfig wlan0 txpower 18dBm

or

sudo iwconfig wlan0 txpower auto

?

Also watch temperatures.

PS: of course use the actual device name instead of "wlan0"

Last edited by seth (2017-05-19 06:15:50)

doginpants · 2017-05-19 17:25:41

Edit: I jumped the gun, the issue still is present on both auto and 18dBm. Also the issue may not be directly linked to network activity, I am a bit at a loss. When creating a android studio project the screen flickers, and with no network connection it does not flicker. It seems like this wouldn't have high network usage but I could be wrong.

Last edited by doginpants (2017-05-19 17:39:33)

seth · 2017-05-19 17:37:46

I googled up the driver and found https://bbs.archlinux.org/viewtopic.php?id=191077&p=2 with complaints about overheating - sounded interesting enough and apparently the default is 1496 dBm ...
The device is driven at its HW maximum power what is not nearly covered by the electromagnetic shielding of the internal antenna of a notebook.

Thus the pattern fit and the suggested solution is reasonable

The setting gets lost with a reboot.
You can however add a modprobe configlet that overrides the install command to run a script which insmod's the module and sets the txpower afterwards.
See https://wiki.archlinux.org/index.php/Kernel_modules and "man modprobe.conf"

Ok, so much for this hunch, sorry. However ensure that nothing resets the txpower (eg. some powersaving feature - there's module option for this)

Last edited by seth (2017-05-19 17:39:24)

doginpants · 2017-05-19 17:40:21

Would something like TLP be changing it? Also do you know which parameter I need to set?

Last edited by doginpants (2017-05-19 17:53:37)

seth · 2017-05-19 18:55:58

Possibly ("idk, but possibly")

See "modinfo brcmfmac", but I was wrong, the module has no power saving parameters.

Arch Linux

#1 2017-05-16 16:50:19

Connecting to network causes screen flickering

#2 2017-05-16 18:19:35

Re: Connecting to network causes screen flickering

#3 2017-05-17 20:35:00

Re: Connecting to network causes screen flickering

#4 2017-05-18 05:42:33

Re: Connecting to network causes screen flickering

#5 2017-05-19 05:22:04

Re: Connecting to network causes screen flickering

#6 2017-05-19 06:14:22

Re: Connecting to network causes screen flickering

#7 2017-05-19 17:25:41

Re: Connecting to network causes screen flickering

#8 2017-05-19 17:37:46

Re: Connecting to network causes screen flickering

#9 2017-05-19 17:40:21

Re: Connecting to network causes screen flickering

#10 2017-05-19 18:55:58

Re: Connecting to network causes screen flickering

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