RE: [PATCH 1/1] iommu/vt-d: Skip TE disabling on quirky gfx dedicated iommu

[Limonciello, Mario]

> -----Original Message-----
> From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Sent: Tuesday, July 21, 2020 6:07 PM
> To: Limonciello, Mario; Joerg Roedel
> Cc: baolu.lu@xxxxxxxxxxxxxxx; Ashok Raj; linux-kernel@xxxxxxxxxxxxxxx;
> stable@xxxxxxxxxxxxxxx; Koba Ko; iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx
> Subject: Re: [PATCH 1/1] iommu/vt-d: Skip TE disabling on quirky gfx dedicated
> iommu
> 
> 
> [EXTERNAL EMAIL]
> 
> Hi Limonciello,
> 
> On 7/21/20 10:44 PM, Limonciello, Mario wrote:
> >> -----Original Message-----
> >> From: iommu<iommu-bounces@xxxxxxxxxxxxxxxxxxxxxxxxxx>  On Behalf Of Lu
> >> Baolu
> >> Sent: Monday, July 20, 2020 7:17 PM
> >> To: Joerg Roedel
> >> Cc: Ashok Raj;linux-kernel@xxxxxxxxxxxxxxx;stable@xxxxxxxxxxxxxxx; Koba
> >> Ko;iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx
> >> Subject: [PATCH 1/1] iommu/vt-d: Skip TE disabling on quirky gfx dedicated
> >> iommu
> >>
> >> The VT-d spec requires (10.4.4 Global Command Register, TE field) that:
> >>
> >> Hardware implementations supporting DMA draining must drain any in-flight
> >> DMA read/write requests queued within the Root-Complex before completing
> >> the translation enable command and reflecting the status of the command
> >> through the TES field in the Global Status register.
> >>
> >> Unfortunately, some integrated graphic devices fail to do so after some
> >> kind of power state transition. As the result, the system might stuck in
> >> iommu_disable_translation(), waiting for the completion of TE transition.
> >>
> >> This provides a quirk list for those devices and skips TE disabling if
> >> the qurik hits.
> >>
> >> Fixes:https://bugzilla.kernel.org/show_bug.cgi?id=208363
> > That one is for TGL.
> >
> > I think you also want to add this one for ICL:
> > Fixes:https://bugzilla.kernel.org/show_bug.cgi?id=206571
> >
> 
> Do you mean someone have tested that this patch also fixes the problem
> described in 206571?
> 

Yes, confusingly https://bugzilla.kernel.org/show_bug.cgi?id=208363#c31 actually
is the XPS 9300 ICL system and issue.

I also have a private confirmation from another person that it resolves it for
them on another ICL platform.

Christian, maybe you can add a tested by clause for the ICL testing.