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vgaarb: a NULL bridge is acceptable for root devices. 

I assumed all PCI buses had a bridge, but playing with qemu recently, I
discovered vgaarb bug where it wasn't detecting both devices shared a bridge
at the root level.

Don't check for NULL, if two buses have a NULL bridge, assume they share the
root bus.

Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This commit is contained in:
Dave Airlie 2011-10-10 09:29:18 +01:00
parent d53dab3ae1
commit f6252114cb
1 changed files with 21 additions and 23 deletions
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44
drivers/gpu/vga/vgaarb.c
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@ -465,31 +465,29 @@ static void vga_arbiter_check_bridge_sharing(struct vga_device *vgadev)
while (new_bus) {
new_bridge = new_bus->self;
if (new_bridge) {
/* go through list of devices already registered */
list_for_each_entry(same_bridge_vgadev, &vga_list, list) {
bus = same_bridge_vgadev->pdev->bus;
/* go through list of devices already registered */
list_for_each_entry(same_bridge_vgadev, &vga_list, list) {
bus = same_bridge_vgadev->pdev->bus;
bridge = bus->self;
/* see if the share a bridge with this device */
if (new_bridge == bridge) {
/* if their direct parent bridge is the same
as any bridge of this device then it can't be used
for that device */
same_bridge_vgadev->bridge_has_one_vga = false;
}
/* now iterate the previous devices bridge hierarchy */
/* if the new devices parent bridge is in the other devices
hierarchy then we can't use it to control this device */
while (bus) {
bridge = bus->self;
/* see if the share a bridge with this device */
if (new_bridge == bridge) {
/* if their direct parent bridge is the same
as any bridge of this device then it can't be used
for that device */
same_bridge_vgadev->bridge_has_one_vga = false;
}
/* now iterate the previous devices bridge hierarchy */
/* if the new devices parent bridge is in the other devices
hierarchy then we can't use it to control this device */
while (bus) {
bridge = bus->self;
if (bridge) {
if (bridge == vgadev->pdev->bus->self)
vgadev->bridge_has_one_vga = false;
}
bus = bus->parent;
if (bridge) {
if (bridge == vgadev->pdev->bus->self)
vgadev->bridge_has_one_vga = false;
}
bus = bus->parent;
}
}
new_bus = new_bus->parent;