Re: [Xen-devel] [BUG] After upgrade to Xen 4.12.0 iommu=no-igfx

[Roman Shaposhnik <roman@xxxxxxxxxx>]

On Mon, Aug 19, 2019 at 1:16 AM Roger Pau Monné <roger.pau@xxxxxxxxxx> wrote:
>
> On Sun, Aug 18, 2019 at 10:00:17PM -0700, Roman Shaposhnik wrote:
> > Hi Roger!
> >
> > Some good news, some bad news ;-)
> >
> > Good news is that on the newer BIOS, your original patch seems to work fine.
> >
> > IOW, with newer BIOS:
> >     1. without your original patch I see garbled screen
> >     2. with your original patch everything boots normally.
>
> That would be my expectation.
>
> > Bad news is that with older BIOS, your original patch seems to either
> > work or not depending on the BIOS some of the BIOS settings.
> >
> > IOW, with older BIOS:
> >     1. without your original patch I see garbled screen (regardless of
> > BIOS settings)
> >     2. with your original patch AND resetting to a factory defaults of
> > BIOS settings -- everything boots normally
> >     3. when I load up our custom settings -- the only thing that can
> > boot normally is the latest patch
> >
> > So, would it make sense and commit your original patch for now? This
> > will unlock me with newer BIOSes on these boxes.
>
> I think so, can you please provide a tested-by to the patch:
>
> https://lists.xenproject.org/archives/html/xen-devel/2019-07/msg01547.html

Done.

> Feel free to also note the weird behaviour you are seeing with this
> box and firmware version.
>
> > As for the older BIOSes, I still feel that it would be great for Xen
> > to boot more reliably -- especially since Xen 4.10 seems to be doing
> > fine regardless of BIOS version and settings.
> >
> > What do you think?
>
> We could add a quirk for this fimrware version and hardware if we know
> exactly what the issue is. Have you figured out if it's related to the
> flush? ie: iommu_iotlb_flush vs iommu_iotlb_flush_all vs iommu_flush_all?

I am actually at Open Source Summit in San Diego right now -- away from
my lab. I'll try to capture as much data on Fri as possible when I come back.

Please stay tuned.

Thanks,
Roman.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel