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