I also experience flickering/glitches with my Intel i7-10700k.
```
$ lspci -nnk | grep -A3 VGA
00:02.0 VGA compatible controller [0300]: Intel Corporation CometLake-S GT2
[UHD Graphics 630] [8086:9bc5] (rev 05)
DeviceName: Onboard - Video
Subsystem: ASUSTeK Computer Inc. CometLake-S GT2 [UHD Graphics 630]
[1043:8694]
Kernel driver in use: i915
```
In my case I often see a glitchy horizontal line about a quarter of the
way down from the top of the monitor screen. It is most prevalent when
I use the mouse to drag a window through this region.
This system was upgraded through successive Kubuntu LTS versions until
finally arriving at Kubuntu 24.04.1.
I tried the various changes to /etc/default/grub including
`intel_iommu=igfx_off` and the flickering remained.
Interestingly if I boot from a USB flash drive with the
kubuntu-24.04.1-desktop-amd64.iso image then I do not experience any
flickering.
Following are some differences in packages that I noticed that may or
may not be relevant to the problem.
Output from `uname -a` on USB flash drive (upper) and on (lower)
----------------------------------------------------------------
Linux kubuntu 6.8.0-41-generic #41-Ubuntu SMP PREEMPT_DYNAMIC Fri Aug 2
20:41:06 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux
Linux kaby 6.8.0-51-generic #52-Ubuntu SMP PREEMPT_DYNAMIC Thu Dec 5
13:09:44 UTC 2024 x86_64 x86_64 x86_64 GNU/Linux
Output from ` dpkg -l | grep -i intel | grep -vi intelligent`
-------------------------------------------------------------
on USB flash drive (no flickering)
----------------------------------
```
ii firmware-sof-signed 2023.12.1-1ubuntu1
all Intel SOF firmware - signed
ii i965-va-driver:amd64
2.4.1+dfsg1-1build2 amd64 VAAPI driver for Intel
G45 & HD Graphics family
ii intel-media-va-driver:amd64 24.1.0+dfsg1-1
amd64 VAAPI driver for the Intel GEN8+ Graphics
family
ii intel-microcode
3.20240813.0ubuntu0.24.04.2 amd64 Processor microcode
firmware for Intel CPUs
ii iucode-tool 2.3.1-3build1
amd64 Intel processor microcode tool
ii libdrm-intel1:amd64 2.4.120-2build1
amd64 Userspace interface to intel-specific
kernel DRM services -- runtime
ii libigdgmm12:amd64 22.3.17+ds1-1
amd64 Intel Graphics Memory Management Library
-- shared library
ii libipt2 2.0.6-1build1
amd64 Intel Processor Trace Decoder Library
ii xserver-xorg-video-intel
2:2.99.917+git20210115-1build1 amd64 X.Org X server --
Intel i8xx, i9xx display driver
```
on SSD (yes flickering)
-----------------------
```
ii firmware-sof-signed
2023.12.1-1ubuntu1.3 all Intel SOF firmware -
signed
ii i965-va-driver:amd64
2.4.1+dfsg1-1build2 amd64 VAAPI driver for Intel
G45 & HD Graphics family
ii i965-va-driver:i386
2.4.1+dfsg1-1build2 i386 VAAPI driver for Intel
G45 & HD Graphics family
ii intel-media-va-driver:amd64 24.1.0+dfsg1-1
amd64 VAAPI driver for the Intel GEN8+ Graphics
family
ii intel-media-va-driver:i386 24.1.0+dfsg1-1
i386 VAAPI driver for the Intel GEN8+ Graphics
family
ii intel-microcode
3.20241112.0ubuntu0.24.04.1 amd64 Processor microcode
firmware for Intel CPUs
ii iucode-tool 2.3.1-3build1
amd64 Intel processor microcode tool
ii libdrm-intel1:amd64 2.4.120-2build1
amd64 Userspace interface to intel-specific
kernel DRM services -- runtime
ii libdrm-intel1:i386 2.4.120-2build1
i386 Userspace interface to intel-specific
kernel DRM services -- runtime
ii libigdgmm12:amd64 22.3.17+ds1-1
amd64 Intel Graphics Memory Management Library
-- shared library
ii libigdgmm12:i386 22.3.17+ds1-1
i386 Intel Graphics Memory Management Library
-- shared library
ii libipt2 2.0.6-1build1
amd64 Intel Processor Trace Decoder Library
ii xserver-xorg-video-intel
2:2.99.917+git20210115-1build1 amd64 X.Org X server --
Intel i8xx, i9xx display driver
```
Key differences I noticed in the "intel packages" were:
- firmware-sof-signed: 2023.12.1-1ubuntu1 versus
2023.12.1-1ubuntu1.3
- intel-microcode: 3.20240813.0ubuntu0.24.04.2 versus
3.20241112.0ubuntu0.24.04.1
- Also extra i386 packages on my SSD.
Hopefully this information will help to troubleshoot.
If more information is needed then let me know.
--
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux-hwe-6.8 in Ubuntu.
https://bugs.launchpad.net/bugs/2062951
Title:
Random flickering with Intel i915 (Gen4+ GPUs) on Linux
Status in Linux:
New
Status in linux package in Ubuntu:
Fix Released
Status in linux-hwe-6.8 package in Ubuntu:
Confirmed
Status in linux source package in Jammy:
Confirmed
Status in linux-hwe-6.8 source package in Jammy:
Fix Released
Status in linux source package in Noble:
Fix Released
Status in linux-hwe-6.8 source package in Noble:
Confirmed
Status in linux source package in Oracular:
Fix Released
Status in linux-hwe-6.8 source package in Oracular:
Confirmed
Bug description:
SRU Justification
[Impact]
The flickering predominantly occurs when the mouse cursor is in the bottom
quarter of the screen and stops when the cursor leaves this area.
Extensive testing across various kernel versions revealed that the issue
became apparent from kernel version 6.8.0 onward, correlating with the
mentioned configuration changes, CONFIG_INTEL_IOMMU_DEFAULT_ON and
CONFIG_INTEL_IOMMU_SCALABLE_MODE_DEFAULT_ON.
The problem persists in the latest drm tip.
[Fix]
As an immediate workaround, adding 'intel_iommu=igfx_off' to the kernel
command line has been found to effectively eliminate the flickering issue.
This patch proposes the same behavior as 'intel_iommu=igfx_off' and apply the
rule to all Intel SKL GPU IDs.
[Test]
1. Boot up to desktop with 6.8.0-x kernels
2. Moving cursor around the desktop
3. There should be no flicker while cursor is moving
[Where problems could occur]
For virtualized environments using hardware-assisted virtualization for
graphics (such as VFIO or mediated pass-through), disabling IOMMU for graphics
could either disable these features or reduce their security and efficiency.
Usually, users pass the 'intel_iommu=on' by themselves when they are using
related features. So, the impact of this change is minimal.
===========
After migrating Mantic 23.10 install to Linux 6.8.0, I am experiencing heavy
flickering at random.
It happens after a moderate to heavy on screen activity like window
switching, scrolling etc.
It never happens when playing video or when there is no interaction using
keyboard/pointer.
It tend to happen when the mouse cursor is in the bottom quarter of the
screen and stops immediately when the cursor leaves that screen region.
Around the same time the following appears in kernel log:
kernel: i915 0000:00:02.0: [drm] *ERROR* CPU pipe A FIFO underrun
Happens on both X11 and Wayland on both KDE plasma and Mate (though
less).
I first encountered the issue with Linux 6.8.0-11 and it still happens with
Ubunutu's 6.8.0-28 and Mainline 6.8.7.
Kernels 6.6, 6.5, 6.1 and older did not have that issue.
Hardware is: Dell XPS 9350, Vendor Intel, Driver i915, Skylake GT2 [HD
Graphics 520]
Software: Ubuntu 23.10, KDE Plasma 5.27.10 / Mate 1.26
Attaching kernel log for 6.8.0-28
To manage notifications about this bug go to:
https://bugs.launchpad.net/linux/+bug/2062951/+subscriptions
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