[Bug 101391] Lockup after resume (kernel BUG at include/drm/drm_mm.h:145!)

[bugzilla-daemon at bugzilla.kernel.org]

https://bugzilla.kernel.org/show_bug.cgi?id=101391

--- Comment #5 from Michael Long <harn-solo at gmx.de> ---
I managed to proceed with the bisect process but it doesn't lead to another bad
commit. 

After that I restarted the bisection but this time without limiting to a
sub-tree. This time e640a280ccb9c448a3d9d522ea730ce00efa8cf0 (Merge branch
'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux)
was the first bad commit, but continuing also did not reveal another bad
commit. 

I'm not really familiar with the process, so I might do something fundamentally
wrong but I will try again.

But I found out the following:

For testing around with KVM-based vga-passthrough, I've installed three
different GPUs in my system:

AMD Radeon HD 5430 card for the host (using radeon)
AMD Radeon HD 5570 card for VM1 (using radeon) or another NVIDIA based card
(using nouveau)
NVIDIA GTX 980 card for VM2 (no driver bound)

Hence the GTX 980 is not supported well, it is stubbed out via kernel parameter
pci-stub.ids=...., the other cards were bound to a driver when they are not
used with KVM/qemu.

The problem ONLY arises when more than 2 GPUs are installed (my guess is seen
by vgaarb) and at least 2 GPUs are bound to a driver, e.g. radeon or nouveau. 

If both cards are stubbed out the resume problem does not occur. I could do
this as a temporary workaround but then I run into this bug here:
https://bugs.freedesktop.org/show_bug.cgi?id=88773

I'm absolutely aware that this is corner case but still, it works with 4.0.9.

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