Public bug reported:
[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.
** Affects: linux (Ubuntu)
Importance: Undecided
Assignee: AceLan Kao (acelankao)
Status: In Progress
** Affects: linux (Ubuntu Jammy)
Importance: Undecided
Status: Invalid
** Affects: linux (Ubuntu Noble)
Importance: Undecided
Assignee: AceLan Kao (acelankao)
Status: In Progress
** Affects: linux (Ubuntu Oracular)
Importance: Undecided
Assignee: AceLan Kao (acelankao)
Status: In Progress
** Affects: linux (Ubuntu Plucky)
Importance: Undecided
Assignee: AceLan Kao (acelankao)
Status: In Progress
** Also affects: linux (Ubuntu Jammy)
Importance: Undecided
Status: New
** Also affects: linux (Ubuntu Oracular)
Importance: Undecided
Status: New
** Also affects: linux (Ubuntu Plucky)
Importance: Undecided
Status: New
** Also affects: linux (Ubuntu Noble)
Importance: Undecided
Status: New
** Changed in: linux (Ubuntu Jammy)
Status: New => Invalid
** Changed in: linux (Ubuntu Noble)
Status: New => In Progress
** Changed in: linux (Ubuntu Noble)
Assignee: (unassigned) => AceLan Kao (acelankao)
** Changed in: linux (Ubuntu Oracular)
Status: New => In Progress
** Changed in: linux (Ubuntu Plucky)
Status: New => In Progress
** Changed in: linux (Ubuntu Oracular)
Assignee: (unassigned) => AceLan Kao (acelankao)
** Changed in: linux (Ubuntu Plucky)
Assignee: (unassigned) => AceLan Kao (acelankao)
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https://bugs.launchpad.net/bugs/2086587
Title:
Random flickering with Intel i915 (Comet Lake and Kaby Lake) on Linux
6.8
Status in linux package in Ubuntu:
In Progress
Status in linux source package in Jammy:
Invalid
Status in linux source package in Noble:
In Progress
Status in linux source package in Oracular:
In Progress
Status in linux source package in Plucky:
In Progress
Bug description:
[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.
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2086587/+subscriptions
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