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

[Kai-Heng Feng]

Hi,

> On Mar 13, 2020, at 11:42, Khaled Elmously <khalid.elmously at canonical.com> wrote:
> 
> This does NOT apply cleanly to Bionic. It's a minior conflict in logging syntax, but I don't know what syntax is preferred or if it's important, so I can't resolve it:
> 
> https://pastebin.canonical.com/p/GqjmKvc72N/
> 
> 
> 
> Applied to E only.

Bionic can be skipped, thanks!

Kai-Heng

> 
> 
> 
> On 2020-02-20 16:37:02 , Kai-Heng Feng wrote:
>> 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(-)
>> 
>> -- 
>> 2.17.1
>> 
>> 
>> -- 
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