Re: IGD pass-through failures since 4.10.

["Dr. Greg" <greg@xxxxxxxxxxxx>]

On Wed, Feb 23, 2022 at 09:59:48AM +0100, Jan Beulich wrote:

Hi, I hope the end of the week is going well for everyone.

> On 22.02.2022 19:52, Dr. Greg wrote:
> > On Fri, Feb 18, 2022 at 08:04:14AM +0100, Jan Beulich wrote:
> >> On 17.02.2022 21:15, Dr. Greg wrote:
> >>> On Mon, Feb 14, 2022 at 09:56:34AM +0100, Jan Beulich wrote:
> >>> In the case of the logs above, the following command sequence is being
> >>> executed upon termination of the domain:
> >>>
> >>> # Unbind devices.
> >>> echo 0000:00:14.0 >| /sys/bus/pci/drivers/pciback/unbind
> >>> echo 0000:00:02.0 >| /sys/bus/pci/drivers/pciback/unbind
> >>>
> >>> # Rebind devices.
> >>> echo 0000:00:14.0 >| /sys/bus/pci/drivers/xhci_hcd/bind
> >>> echo 0000:00:02.0 >| /sys/bus/pci/drivers/i915/bind
> > 
> >> ... you may still want to try replacing these with
> >> "xl pci-assignable-add ..." / "xl pci-assignable-remove ...".
> > 
> > We tested using the 'xl pci-assignable-add/remove' sequences and we
> > believe this may have resulted in the proper return of the devices to
> > dom0 but haven't been able to verify that since the Windows VM is now
> > throwing the VIDEO_TDR error.
> > 
> > Unless we are misunderstanding something the 'xl
> > pci-assignable-remove' sequence requires the manual re-binding of the
> > devices to their dom0 drivers.

> Hmm, I thought drivers would be rebound, but I'm not a tool stack
> person.  Looking at libxl__device_pci_assignable_remove() at least
> support this assumption of mine. You did use the command's -r
> option, didn't you?

No we weren't and I now see the -r option.

We have already re-worked our setup scripts to use pci-assignable-add
and will verify the -r option works as advertised, thanks for the tip.

We had our lab machine broken for a couple of days where it wouldn't
start an IGD pass-through session in any way shape or form.  We got
that sorted out and will now go back to 4.15.2 and verify what works
and doesn't work and report back.

> Jan

Have a good weekend.

As always,
Dr. G.W. Wettstein, Ph.D.   Enjellic Systems Development, LLC.
4206 N. 19th Ave.           Specializing in information infra-structure
Fargo, ND  58102            development.
PH: 701-281-1686            EMAIL: greg@xxxxxxxxxxxx
------------------------------------------------------------------------------
"On the other hand, the Linux philosophy is 'laugh in the face of
 danger'.  Oops.  Wrong one.  'Do it yourself'.  Thats it."
                                -- Linus Torvalds