Hi,
diff --git a/drivers/video/aperture.c b/drivers/video/aperture.c
index f42a0d8bc211..101e13c2cf41 100644
--- a/drivers/video/aperture.c
+++ b/drivers/video/aperture.c
@@ -8,6 +8,7 @@
#include <linux/pci.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
+#include <linux/sysfb.h>
#include <linux/types.h>
#include <linux/vgaarb.h>
@@ -286,7 +287,20 @@ int
aperture_remove_conflicting_devices(resource_size_t base,
resource_size_t si
#if IS_REACHABLE(CONFIG_FB)
struct apertures_struct *a;
int ret;
+#endif
+
+ /*
+ * 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:
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.
I do not quite understand the comment justifying the call.
Some discussions with workarounds:
https://old.reddit.com/r/VFIO/comments/11qei4t/framebuffer_doesnt_work_anymore_after_passthrough/
https://bbs.archlinux.org/viewtopic.php?id=280512
Thanks,
Samuel
