Thomas Zimmermann [off-list ref] writes:

[...]

quoted

quoted

+    /*
+     * If a driver asked to unregister a platform device registered by
+     * sysfb, then can be assumed that this is a driver for a display
+     * that is set up by the system firmware and has a generic driver.
+     *
+     * Drivers for devices that don't have a generic driver will never
+     * ask for this, so let's assume that a real driver for the display
+     * was already probed and prevent sysfb to register devices later.
+     */
+    sysfb_disable();

This call to sysfb_disable() has been causing trouble with regard to
VFIO. VFIO has been calling aperture_remove_conflicting_pci_devices to
get rid of any console drivers (d173780620792c) using the device in
question, but now even unrelated drivers are getting killed. Example
situation:

Which drivers do you use?

Also, what kernel version?

[...]

quoted

Machine has two GPUs and uses efifb for the console. Efifb registers
with the aperture system the efi framebuffer region, which is covered
by a BAR resource of GPU 1. VFIO grabs GPU 2 and calls
aperture_remove_conflicting_pci_devices(GPU 2). GPU 2 has no overlap
with the efifb on GPU1 but the efifb is killed regardless due to
the unconditional call to sysfb_disable(). The console switches
to dummy and locks up from the user perspective.
This seems unnecessary, as the device is unrelated.

That's a bug indeed but I thought that was already fixed...

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat