Messages in this thread | | | Subject | Re: [PATCH v2] iommu/amd: Disable IOMMU on Stoney Ridge systems | From | Kai-Heng Feng <> | Date | Fri, 6 Dec 2019 13:57:41 +0800 |
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Hi Joerg,
> On Dec 3, 2019, at 01:00, Christoph Hellwig <hch@infradead.org> wrote: > > On Fri, Nov 29, 2019 at 10:21:54PM +0800, Kai-Heng Feng wrote: >> Serious screen flickering when Stoney Ridge outputs to a 4K monitor. >> >> According to Alex Deucher, IOMMU isn't enabled on Windows, so let's do >> the same here to avoid screen flickering on 4K monitor. > > Disabling the IOMMU entirely seem pretty severe. Isn't it enough to > identity map the GPU device?
Ok, there's set_device_exclusion_range() to exclude the device from IOMMU. However I don't know how to generate range_start and range_length, which are read from ACPI.
Can you please give me some advice here?
Kai-Henge
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