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Date:   Mon, 2 Dec 2019 09:00:11 -0800
From:   Christoph Hellwig <hch@infradead.org>
To:     Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc:     joro@8bytes.org, Alex Deucher <alexander.deucher@amd.com>,
        iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] iommu/amd: Disable IOMMU on Stoney Ridge systems
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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?