Re: [PATCH] iommu/vt-d: Add RPLS to quirk list to skip TE disabling

["Vivi, Rodrigo" <rodrigo.vivi@intel.com>]

On Fri, 2022-02-25 at 10:20 +0800, Lu Baolu wrote:
> On 2/24/22 9:39 PM, Vivi, Rodrigo wrote:
> > On Thu, 2022-02-24 at 13:42 +0800, Lu Baolu wrote:
> > > On 2/23/22 2:29 PM, Tejas Upadhyay wrote:
> > > > 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_translati
> > > > on(), waiting for the completion of TE transition.
> > > > 
> > > > This adds RPLS to a quirk list for those devices and skips
> > > > TE disabling if the qurik hits.
> > > > 
> > > > Fixes: https://gitlab.freedesktop.org/drm/intel/-/issues/4898
> > > > Fixes: LCK-10789
> > > 
> > > Remove this please.
> > 
> > good catch. Wrong use of Fixes tag.
> > "Fixes:" should only be used for patches fixing other patches and
> > mentioning the commit id.
> 
> This is still a fix patch, right? If so,
> 
> Fixes: b1012ca8dc4f9 "iommu/vt-d: Skip TE disabling on quirky gfx 
> dedicated iommu"
> Cc: stable@vger.kernel.org

hm... you have a point, but I'm not comfortable with this because
for me it is like an addition of a pci id of a new platform.
Older kernels won't have the support for that anyway.
and if for every new platform we add here we need to blame this
b1012ca8dc4f9 (which did the right time when it was created)
it doesn't look fair to me.

> 

> > 
> > Baolu,
> > could you mind if we use
> > 
> > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/4898
> > 
> > or maybe
> > 
> > References: https://gitlab.freedesktop.org/drm/intel/-/issues/4898
> > 
> > This last one seems to be the one use in drivers/iommu
> > and the Closes is what we use in drm-intel, hence the one used
> > with gitlab.freedesktop links in general.
> 
> How about "Link:"?
> 
> As Documentation/process/submitting-patches.rst states:
> 
> If related discussions or any other background information behind the
> change
> can be found on the web, add 'Link:' tags pointing to it. In case
> your patch
> fixes a bug, for example, add a tag with a URL referencing the report
> in the
> mailing list archives or a bug tracker; if the patch is a result of
> some
> earlier mailing list discussion or something documented on the web,
> point to
> it.

yeap, "Link:" works well too.

With these changes could we get your ack to merge to drm-intel?

or do you prefer to go through your iommu path?

> 
> 
> > 
> > > 
> > > > Tested-by: Raviteja Goud Talla <ravitejax.goud.talla@intel.com>
> > > > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > > > Signed-off-by: Tejas Upadhyay
> > > > <tejaskumarx.surendrakumar.upadhyay@intel.com>
> > 
> > you can keep my rv-b
> > 
> > > > ---
> > > >    drivers/iommu/intel/iommu.c | 2 +-
> > > >    1 file changed, 1 insertion(+), 1 deletion(-)
> > > > 
> > > > diff --git a/drivers/iommu/intel/iommu.c
> > > > b/drivers/iommu/intel/iommu.c
> > > > index 92fea3fbbb11..be9487516617 100644
> > > > --- a/drivers/iommu/intel/iommu.c
> > > > +++ b/drivers/iommu/intel/iommu.c
> > > > @@ -5743,7 +5743,7 @@ static void
> > > > quirk_igfx_skip_te_disable(struct
> > > > pci_dev *dev)
> > > >          ver = (dev->device >> 8) & 0xff;
> > > >          if (ver != 0x45 && ver != 0x46 && ver != 0x4c &&
> > > >              ver != 0x4e && ver != 0x8a && ver != 0x98 &&
> > > > -           ver != 0x9a)
> > > > +           ver != 0x9a && ver != 0xa7)
> > > >                  return;
> > > >    
> > > >          if (risky_device(dev))
> > > 
> > > This is a quirk for integrated graphic device. Rodrigo, does this
> > > hardware needs this quirk as well?
> > 
> > Yes, 0xa7* are RPL-S that are integrated and very similar to 0x46*
> > (ADL-S)
> 
> Thank you for confirming this quirk.
> 
> > 
> > I would prefer to have a more expanded list instead of group or at
> > least some defines with the platform names.
> 
> Yeah! That's better.

could be done in a follow up right?!

Thanks,
Rodrigo.

> 
> Best regards,
> baolu

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