udlfb: remove sysfs framebuffer device with USB .disconnect()
authorKay Sievers <kay.sievers@vrfy.org>
Sat, 28 Jan 2012 19:57:46 +0000 (19:57 +0000)
committerDave Airlie <airlied@redhat.com>
Thu, 15 Mar 2012 13:35:22 +0000 (13:35 +0000)
commitce880cb860f36694d2cdebfac9e6ae18176fe4c4
tree6fa674bd935d7f4c48dec243970c6b0b92f0c0a7
parent8229c885fe361e521ac64de36b16011e54a30de0
udlfb: remove sysfs framebuffer device with USB .disconnect()

The USB graphics card driver delays the unregistering of the framebuffer
device to a workqueue, which breaks the userspace visible remove uevent
sequence. Recent userspace tools started to support USB graphics card
hotplug out-of-the-box and rely on proper events sent by the kernel.

The framebuffer device is a direct child of the USB interface which is
removed immediately after the USB .disconnect() callback. But the fb device
in /sys stays around until its final cleanup, at a time where all the parent
devices have been removed already.

To work around that, we remove the sysfs fb device directly in the USB
.disconnect() callback and leave only the cleanup of the internal fb
data to the delayed work.

Before:
 add      /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2 (usb)
 add      /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0 (usb)
 add      /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0/graphics/fb0 (graphics)
 remove   /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0 (usb)
 remove   /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2 (usb)
 remove   /2-1.2:1.0/graphics/fb0 (graphics)

After:
 add      /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2 (usb)
 add      /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0 (usb)
 add      /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0/graphics/fb1 (graphics)
 remove   /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0/graphics/fb1 (graphics)
 remove   /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0 (usb)
 remove   /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2 (usb)

Cc: stable@vger.kernel.org
Tested-by: Bernie Thompson <bernie@plugable.com>
Acked-by: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
drivers/video/fbmem.c
drivers/video/udlfb.c
include/linux/fb.h