From c548795abe0d3520b74e18f23ca0a0d72deddab9 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Wed, 9 Jun 2010 17:34:27 -0400 Subject: [PATCH] USB: add check to detect host controller hardware removal This patch (as1391) fixes a problem that can occur when USB host controller hardware is hot-unplugged. If no interrupts are generated by the unplug then the HCD may not realize that the controller is gone, and the subsequent unbind may hang waiting for interrupts that never arrive. The solution (for PCI-based controllers) is to call the HCD's interrupt handler at the start of usb_hcd_pci_remove(). If the hardware is gone, the handler will realize this when it tries to read the controller's status register. Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/hcd-pci.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/usb/core/hcd-pci.c b/drivers/usb/core/hcd-pci.c index 1cf2d1e79a5c..7e2d5271b0c9 100644 --- a/drivers/usb/core/hcd-pci.c +++ b/drivers/usb/core/hcd-pci.c @@ -292,6 +292,14 @@ void usb_hcd_pci_remove(struct pci_dev *dev) if (!hcd) return; + /* Fake an interrupt request in order to give the driver a chance + * to test whether the controller hardware has been removed (e.g., + * cardbus physical eject). + */ + local_irq_disable(); + usb_hcd_irq(0, hcd); + local_irq_enable(); + usb_remove_hcd(hcd); if (hcd->driver->flags & HCD_MEMORY) { iounmap(hcd->regs);