From: Kai-Heng Feng <kai.heng.feng@canonical.com>
To: Joerg Roedel <joro@8bytes.org>
Cc: Alex Deucher <alexander.deucher@amd.com>,
iommu@lists.linux-foundation.org,
Kernel development list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] iommu/amd: Disable IOMMU on Stoney Ridge systems
Date: Fri, 6 Dec 2019 13:57:41 +0800 [thread overview]
Message-ID: <974A8EB3-70B6-4A33-B36C-CFF69464493C@canonical.com> (raw)
In-Reply-To: <20191202170011.GC30032@infradead.org>
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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next prev parent reply other threads:[~2019-12-06 5:57 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-29 14:21 [PATCH v2] iommu/amd: Disable IOMMU on Stoney Ridge systems Kai-Heng Feng
2019-12-01 12:42 ` Lucas Stach
2019-12-02 16:36 ` Deucher, Alexander
2019-12-04 16:08 ` Deucher, Alexander
2019-12-06 5:59 ` Kai-Heng Feng
2019-12-06 8:57 ` Christian König
2019-12-02 17:00 ` Christoph Hellwig
2019-12-06 5:57 ` Kai-Heng Feng [this message]
2019-12-17 9:53 ` Joerg Roedel
2019-12-18 17:45 ` Kai-Heng Feng
2019-12-19 19:15 ` Deucher, Alexander
2019-12-20 2:13 ` Kai-Heng Feng
2020-01-06 8:37 ` Kai-Heng Feng
2020-02-05 10:10 ` Kai-Heng Feng
2020-02-05 13:24 ` Joerg Roedel
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