Regression in 3.9~rc1 on some NVIDIA Pascal graphics cards
This is being discussed on tails-testers@ (Subject: Nvidia Pascal no longer loads gdm) + I've received some more data privately (Subject: Clean Tails 3.8 Nvidia Pascal dump.
Revert to Stretch's X.Org nouveau video driver (refs: #15833)
It seems that the regression brought by the upgraded one
is worse than the improvements reported after my call for testing.
GTX 1070 ti aka.
07:00.0 VGA compatible controller : NVIDIA Corporation GP104 [10de:1b82] (rev a1) aka. NV134:
- in 3.8, "ran stable, if poorly", using the modesetting X.Org driver in Tails 3.8 because
Unknown chipset: NV134and
[drm] Failed to open DRM device for pci:0000:07:00.0: -13
- in 3.9~rc1, various issues that the OP is debugging and sending me info about
The call for testing for the nouveau upgrade showed only 1 significant improvement that was improved performance on GTX 1080.
But now we see a severe regression with GTX 1070 ti: GDM won't load unless one pass:
modeset=0, which makes X.Org fall back to the fbdev driver
The latter is probably better.
- Assignee changed from intrigeri to segfault
- % Done changed from 10 to 50
- QA Check set to Ready for QA
According to Soul Null's report on the topic branch on GTX 1070 ti:
- If we "downgrade" the nouveau driver to the version from Stretch that was shipped in Tails 3.8, we're back to square one i.e. Tails boots fine, uses the modesetting driver, and #14910 is back.
- Even with the newest version of everything involved (Arch Linux), there are lots of stability issues on GTX 1070 Ti and GTX 710 when using the nouveau driver, which suggests that the ecosystem is not ready to support this hardware properly.
According to #15116#note-42 (the single substantial improvement reported about the nouveau driver upgrade) and #14910#note-16, on 3.9~rc1 and GTX 1080, performance is better but there are still a number of bugs.
Improving performance on one graphics card model is not worth breaking X.Org startup so let's revert to the nouveau driver from Stretch. Once this is merged we should reopen #14910.