[SRU] [B/E/F/Unstable] [PATCH 0/1] Fix AMD Stoney Ridge screen flickering under 4K resolution

[Kai-Heng Feng]

BugLink: https://bugs.launchpad.net/bugs/1864005

[Impact]
Screen flickering/tearing when AMD Stoney Ridge outputs to 4K display.

[Fix]
Disable IOMMU on Stoney Ridge.

[Test]
Connect to 4K screen through DP or HDMI. Heavy flickering/tearing can be
observed.
The flickering/tearing is gone once the patch is applied.

[Regression Potential]
Low. This fix limits to one specific SoC.
According to AMD, IOMMU isn't enabled for this SoC under Windows.
So it's expected behavior.

Kai-Heng Feng (1):
  iommu/amd: Disable IOMMU on Stoney Ridge systems

 drivers/iommu/amd_iommu_init.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

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2.17.1