https://bugzilla.kernel.org/show_bug.cgi?id=84431
Bug ID: 84431 Summary: Kernel crash when unloading radeon module for switcheroo card Product: Drivers Version: 2.5 Kernel Version: all Hardware: All OS: Linux Tree: Mainline Status: NEW Severity: high Priority: P1 Component: Video(DRI - non Intel) Assignee: drivers_video-dri@kernel-bugs.osdl.org Reporter: pali.rohar@gmail.com Regression: No
Created attachment 149991 --> https://bugzilla.kernel.org/attachment.cgi?id=149991&action=edit Fix crash after rmmod radeon on PX systems.
Calling rmmod radeon on PX system cause kernel crash. Reason is function vga_switcheroo_init_domain_pm_ops() which setting dev->pm_domain function of PCI device. When radeon module is unloaded pointer dev->pm_domain is set to vga_switcheroo function which try to call radeon function (which does not exists in memory after rmmod radeon). I bet that nouveau has same problem.
I'm attaching simple patch which set dev->pm_domain of PCI device back to NULL when removing radeon device so vga_switcheroo will not be called.
But I think that proper way for fixing this bug - which is in vga_switcheroo - should be to add function like "vga_switcheroo_exit_domain_pm_ops()" which will set pm_domain back to origin value (which is in my case NULL).
With my patch on PX system I can call rmmod radeon, modprobe radeon, rmmod radeon, ... many times without no crash.