Comment 15 for bug 1712508

Christian,

I am afraid, you may stop trying. Use your time for something more useful.
Sorry, but with a kernel problem, this problem needs to be solved. First.
My interest in workarounds is limited. It is a task of QC to step in for a
remedy to a regression.

On 12 November 2017 at 14:21, Christian <email address hidden> wrote:

> @udippel What project do I need to file the bug into? Their site is
> confusing me.
>
> Or if you opened a bug yourself, I could piggyback onto it.
>
> I also tried some more things today (check askubuntu) and none of it
> worked.
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/1712508
>
> Title:
> Disappearing screen and flickering after upgrade to 16.04
>
> Status in linux package in Ubuntu:
> Confirmed
>
> Bug description:
> I have two Lenovo T410s that I upgraded from 14.04 to 16.04.
> Since then, one is working fine while the other shows mainly an ever
> disappearing screen and flickering.
>
> I have asked here: https://askubuntu.com/questions/947233/i-upgraded-
> from-kubuntu-14-04-lts-to-16-04-lts-and-now-my-screen-
> shows-up-and-di?noredirect=1#comment1506995_947233
> I also found I am not the only one: https://askubuntu.com/
> questions/927407/flickering-screen-with-intel-graphics-on-
> ubuntu-17-04?noredirect=1#comment1507937_927407
> The latter has tried pretty much that could be tried already, to no
> avail.
>
> I think that I can help with this problem, since my two T410s are
> identical in hard- and software, including BIOS, except that one is a
> type 2924 (with NVIDIA-card, though disabled in the BIOS), and the
> other one is a 2904 (without NVIDIA card).
>
> I have checked for differences at boot time and found DMAR as major
> difference:
> T410s, 2924: [ 0.335616] DMAR: Disabling batched IOTLB flush on Ironlake
> T410s, 2904: [ 0.355681] DMAR: BIOS has allocated no shadow GTT;
> disabling IOMMU for graphics
>
> Should this be initially at the root of the problem, I'd consider the
> kernel package as responsible, therefore I marked it as above.
>
> The outputs of lspci -k | grep -EA3 'VGA|3D|Display' are identical to
> the point.
>
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