Bug#962003: *ERROR* Failed to wait for idle; VT'd may hang

[Simon Iremonger (debian)]

On 17/07/2021 15.04, Simon Josefsson wrote:
> Hi. I just installed Debian bullseye daily today (linux-image-amd64
> version 5.10.40-1), and ran into this problem on a Lenovo X201. The
> message repeats every other second or so. I don't notice any other

I believe, the messages/behaviour was slowing the system or so,
not just giving messages, at least I have seen this on X201T.


The workaround is to boot with kernel parameter  intel_iommu=igfx_off

e.g.   set in /etc/default/grub
GRUB_CMDLINE_LINUX_DEFAULT="intel_iommu=igfx_off"
and then  re-run  sudo update-grub and reboot.

[I tend to remove "quiet splash" but you could of course have
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash intel_iommu=igfx_off"


Playing the Git-Bisect game would be helpful if somebody could
find *exactly* where the problem was introduced ..

--Simon

Bug#962003: Bug found still present In current debian Kernels

[Simon Iremonger (debian)]

> Please do test as well the yesterday uploaded 5.8.7-1 but I suspect
> the bug is still present there.
Yes, indeed.

> To isolate the issue it might be worth trying to bisect were the issue
> is introduced and ideally then reported upstream.

Confirmed between 5.4.19-1 and 5.5.13-1.


> Some hints are in
>
https://wiki.debian.org/DebianKernelReportingBugs#Identifying_when_the_bug_was_introduced

"You can find older versions of the kernel in various locations,
including http://snapshot.debian.org.;


Where else are these "various locations" !?!?  Can they be linked
onto above wiki page?  In this case some earlier 5.5's would be
clearly useful test-cases.


Another point that I'd like to see on above page, is -- clear
information on where kernel bugs *should* be filed or *are*
filed with explanation.  I.e.  src:linux  linux-image-amd64
linux-image-VERSION-amd64  and so-on and so-forth!.


Another point that I'd like to see on above page, is clear
information what to do to search for existing kernel bugs,
as "reportbug kernel" would NOT find 962003 for me, this
is related to the above confusion really.


--Simon

Bug#962003: Bug found still present In current debian Kernels

[Simon Iremonger (debian)]

Bug still present, affects for-example X201-Tablet, similar
hardware to T410 with Intel Graphics variant.


Affects at least debian kernels:-

5.6.0-2-amd64   5.6.14-2
5.7.0-2-amd64   5.7.10-1
5.7.0-3-amd64   5.7.17-1

--Simon