From: Ting-Wei Lan <lantw44@gmail.com>
To: "Tian, Kevin" <kevin.tian@intel.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Cc: "Zhang, Yang Z" <yang.z.zhang@intel.com>,
Julien Grall <julien.grall@citrix.com>,
lantw44@gmail.com, Jan Beulich <jbeulich@suse.com>,
Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: [PATCH v2] VT-d: add iommu=igfx option to workaround graphics issues
Date: Fri, 31 Jul 2015 16:37:33 +0800 [thread overview]
Message-ID: <55BB33CD.20008@gmail.com> (raw)
In-Reply-To: <AADFC41AFE54684AB9EE6CBC0274A5D142AB6F79@SHSMSX101.ccr.corp.intel.com>
Tian, Kevin 於 西元2015年07月31日 09:26 寫道:
>> From: Ting-Wei Lan [mailto:lantw44@gmail.com]
>> Sent: Sunday, July 26, 2015 12:58 AM
>>
>> When using Linux >= 3.19 (commit 47591df) as dom0 on some Intel Ironlake
>> devices, It is possible to encounter graphics issues that make screen
>> unreadable or crash the system. It was reported in freedesktop bugzilla:
>>
>> https://bugs.freedesktop.org/show_bug.cgi?id=90037
>>
>> As we still cannot find a proper fix for this problem, this patch adds
>> iommu=igfx option to control whether Intel graphics IOMMU is enabled on
>> these devices. Running Xen with iommu=no-igfx is similar to running
>> Linux with intel_iommu=igfx_off, which disables IOMMU for Intel Ironlake
>> GPU. This can be used by users to manually workaround the problem before
>> a fix is available for i915 driver.
>>
>> Signed-off-by: Ting-Wei Lan <lantw44@gmail.com>
>> ---
>> Changed since v1:
>> * Replace igfx_off with igfx
>>
>> This patch is currently only build-tested because I don't have access to
>> the hardware that have graphics issues this week. I will test this new
>> patch next week.
>>
>> docs/misc/xen-command-line.markdown | 12 +++++++++++-
>> xen/drivers/passthrough/iommu.c | 3 +++
>> xen/drivers/passthrough/vtd/quirks.c | 2 +-
>> xen/include/xen/iommu.h | 2 +-
>> 4 files changed, 16 insertions(+), 3 deletions(-)
>>
>> diff --git a/docs/misc/xen-command-line.markdown
>> b/docs/misc/xen-command-line.markdown
>> index 13f03ad..6262be6 100644
>> --- a/docs/misc/xen-command-line.markdown
>> +++ b/docs/misc/xen-command-line.markdown
>> @@ -793,7 +793,7 @@ debug hypervisor only).
>> > Default: `new` unless directed-EOI is supported
>>
>> ### iommu
>> -> `= List of [ <boolean> | force | required | intremap | qinval | snoop | sharept |
>> dom0-passthrough | dom0-strict | amd-iommu-perdev-intremap | workaround_bios_bug
>> | verbose | debug ]`
>> +> `= List of [ <boolean> | force | required | intremap | qinval | snoop | sharept |
>> dom0-passthrough | dom0-strict | amd-iommu-perdev-intremap | workaround_bios_bug
>> | igfx | verbose | debug ]`
>>
>> > Sub-options:
>>
>> @@ -867,6 +867,16 @@ debug hypervisor only).
>> >> ignored (normally IOMMU setup fails if any of the devices listed by a DRHD
>> >> entry aren't PCI discoverable).
>>
>> +> `igfx` (VT-d)
>> +
>> +> Default: `true`
>> +
>> +>> Enable IOMMU for Intel Calpella/Ironlake devices. This option does not
>> +>> affect grahpics IOMMU on other devices. The intended usage of this option
>> +>> is `no-igfx`, which is silimar to Linux `intel_iommu=igfx_off` option used
>> +>> to workaround graphics issues. If adding `no-igfx` fixes anything, you
>> +>> should file a bug reporting the problem.
>> +
>
> For above description let's make it general, i.e Enable IOMMU for Intel Processor
> Graphics devices. You can list Calpella/Ironlake as the example, but not the only
> target. :-)
no-igfx only works with Calpella/Ironlake because
is_igd_vt_enabled_quirk() contains this code:
if ( !IS_ILK(ioh_id) )
return 1;
The newly added variable iommu_igfx only changes the return value of
is_igd_vt_enabled_quirk() when IS_ILK(ioh_id) is true. I don't know
whether we will need no-igfx on other Intel graphics devices because I
don't many devices to test and I don't have other devices that have this
problem.
>
> Thanks
> Kevin
>
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next prev parent reply other threads:[~2015-07-31 8:37 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-17 19:05 [PATCH] VT-d: add iommu=igfx_off option to workaround graphics issues Ting-Wei Lan
2015-07-17 19:36 ` Andrew Cooper
2015-07-18 8:46 ` 藍挺瑋
2015-07-19 15:53 ` Julien Grall
2015-07-20 8:27 ` Andrew Cooper
2015-07-20 10:19 ` Julien Grall
2015-07-20 1:28 ` Tian, Kevin
2015-07-20 8:21 ` Andrew Cooper
2015-07-20 10:44 ` Ting-Wei Lan
2015-07-21 0:57 ` Tian, Kevin
2015-07-21 6:56 ` Jan Beulich
2015-07-21 7:05 ` Tian, Kevin
2015-07-21 7:16 ` Jan Beulich
2015-07-21 7:23 ` Tian, Kevin
2015-07-21 7:33 ` Jan Beulich
2015-07-23 16:41 ` Ting-Wei Lan
2015-07-20 8:46 ` Jan Beulich
2015-07-25 16:57 ` [PATCH v2] VT-d: add iommu=igfx " Ting-Wei Lan
2015-07-26 16:47 ` Andrew Cooper
2015-07-31 1:26 ` Tian, Kevin
2015-07-31 8:37 ` Ting-Wei Lan [this message]
2015-08-04 2:00 ` Tian, Kevin
2015-08-05 9:11 ` [PATCH v3] " Ting-Wei Lan
2015-08-05 12:18 ` Andrew Cooper
2015-08-05 13:35 ` Wei Liu
2015-08-05 17:10 ` [PATCH v4] " Ting-Wei Lan
2015-08-06 0:49 ` Tian, Kevin
2015-08-06 8:25 ` Wei Liu
2015-08-06 9:28 ` Ian Campbell
2015-07-20 12:12 ` [PATCH] VT-d: add iommu=igfx_off " Andrew Cooper
2015-07-20 12:24 ` Jan Beulich
2015-07-20 12:34 ` Andrew Cooper
2015-07-20 13:55 ` Jan Beulich
2015-07-20 14:12 ` Andrew Cooper
2015-07-20 14:25 ` Jan Beulich
2015-07-21 1:15 ` Tian, Kevin
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