Hi
Am 20.03.23 um 02:47 schrieb Samuel Čavoj:
Hi,
quoted
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
#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:
Which drivers do you use?
Best regards
Thomas
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
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev