Re: Issue about domU missing interrupt

Mats Petersson
Mon, 03 Dec 2012 13:58:07 -0000

On 03/12/12 13:19, Mats Petersson wrote:
> On 03/12/12 13:14, G.R. wrote:
>> On Mon, Dec 3, 2012 at 6:15 PM, Mats Petersson
>> <mats.petersson@citrix.com
<mailto:mats.petersson@citrix.com>> wrote:
>>
>>      On 03/12/12 03:47, G.R. wrote:
>>
>>          Hi developers,
>>          I met some domU issues and the log suggests missing interrupt.
>>          Details from here:
>>          http://www.gossamer-threads.com/lists/xen/users/263938#263938
>>          In summary, this is the suspicious log:
>>
>>          (XEN) vmsi.c:122:d32767 Unsupported delivery mode 3
>>
>>          I''ve checked the code in question and found that mode
3 is an
>>          ''reserved_1'' mode.
>>          I want to trace down the source of this mode setting to
>>          root-cause the issue.
>>          But I''m not an xen developer, and am even a newbie as
a xen user.
>>          Could anybody give me instructions about how to enable
>>          detailed debug log?
>>          It could be better if I can get advice about experiments to
>>          perform / switches to try out etc.
>>
>>          My SW config:
>>          dom0: Debian wheezy (3.6 experimental kernel, xen 4.1.3-4)
>>          domU: Debian wheezy 3.2.x stock kernel.
>>
>>          Thanks,
>>          Timothy
>>
>>      Are you passing hardware (PCI Passthrough) to the HVM guest?
>>      What are the exact messages in the DomU?
>>
>>
>> Yes, I''m doing PCI passthrough (the IGD, audio && USB
controller).
>> But this is actually a PVHVM guest since debian stock kernel has PVOP
>> enabled.
>> And when I tried another PVOP disabled linux distro (openelec v2.0), I
>> did not see such msi related error message.
>> Actually, with that domU I do not see anything obvious wrong from the
>> log, but I also see nothing from panel (panel receive no signal and go
>> power-saving) :-(
>>
>>
>> Back to the issue I was reporting, the domU log looks like this:
>>
>> Dec 2 21:52:44 debvm kernel: [ 1085.604071]
>> [drm:i915_hangcheck_ring_idle]
>> *ERROR* Hangcheck timer elapsed... blt ring idle [waiting on 3354, at
>> 3354], missed IRQ?
>> Dec 2 21:56:50 debvm kernel: [ 1332.076071]
>> [drm:i915_hangcheck_ring_idle]
>> *ERROR* Hangcheck timer elapsed... render ring idle [waiting on 11297,
at
>> 11297], missed IRQ?
>> Dec 2 22:32:48 debvm kernel: [ 7.220073] hda-intel: azx_get_response
>> timeout, switching to polling mode: last cmd=0x000f0000
>> Dec 2 22:45:32 debvm kernel: [ 776.392084] hda-intel: No response from
>> codec, disabling MSI: last cmd=0x002f0600
>> Dec 2 22:45:33 debvm kernel: [ 777.400075] hda_intel: azx_get_response
>> timeout, switching to single_cmd mode: last cmd=0x002f0600
>>
>>
>> Thanks,
>> Timothy
> It does sound like there is a fix in 4.2.0, as indicated by Jan, that
> fixes this. I''m not fully clued up to what the policy for
backporting
> fixes are, and I haven''t looked at the complexity of the fix
itself, but
> either updating to the 4.2.0 or a (personal) backport sounds like the
> right solution here.
I had a quick look, and it doesn''t look that hard to backport that
patch.

--
Mats
>
> Unfortunately, I hadn''t seen Jan''s reply by the time I
wrote my response
> to your original email.
>
> --
> Mats
>
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