https://bugzilla.kernel.org/show_bug.cgi?id=150731
Bug ID: 150731 Summary: amdgpu: segfault on unbind in sysfs; card becomes nonresponsive Product: Drivers Version: 2.5 Kernel Version: 4.6.4 Hardware: x86-64 OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: Video(DRI - non Intel) Assignee: drivers_video-dri@kernel-bugs.osdl.org Reporter: JimiJames.Bove@gmail.com Regression: No
Full details here: https://www.reddit.com/r/linux_gaming/comments/4udupx/nvidiaamd_support_ques...
Summary: I'm using an R9 380. Others confirmed having this issue on the R9 285 and RX 480 (so, Tonga & Polaris 10 at least).
I can bind my video card to amdgpu, and that works. It crashes X, but when I log back in, it's properly connected and everything.
However, if I try to unbind it, after waiting for a few seconds, I get a segfault. Any subsequent attempts to do anything with that card in sysfs--trying to unbind again, trying to bind to something else, etc.--will get stuck forever, never segfaulting, because the card is not responding.
Removing the card (echo 1 > /sys/bus/pci/devices/0000:0X:00.0/remove) works, but after a rescan (echo 1 > /sys/bus/pci/rescan), the card is no longer in sysfs at all, as if it's been powered down. It can't be accessed by the system in any way after that, until the computer reboots.
It may or may not be related to the "reset issues" bug: http://vfio.blogspot.de/2015/04/progress-on-amd-front.html https://lists.gnu.org/archive/html/qemu-devel/2015-04/msg03128.html That bug officially only affects Hawaii and Bonaire, but Tonga cards (380, 285) exhibit the same behavior even if it may not be for the same reason. Whether it affects Polaris 10 (RX 480) is unknown. The RX 480 tester is currently finding that out.
I also had this issue on 4.6.1, so it probably at least affects 4.6 in general. Maybe all kernel versions that have amdgpu?