usb: ohci: Prevent missed ohci interrupts
commit fe81f354 upstream. Testing ohci functionality with qemu's pci-ohci emulation often results in ohci interface stalls, resulting in hung task timeouts. The problem is caused by lost interrupts between the emulation and the Linux kernel code. Additional interrupts raised while the ohci interrupt handler in Linux is running and before the handler clears the interrupt status are not handled. The fix for a similar problem in ehci suggests that the problem is likely caused by edge-triggered MSI interrupts. See commit 0b605572 ("usb: ehci: Prevent missed ehci interrupts with edge-triggered MSI") for details. Ensure that the ohci interrupt code handles all pending interrupts before returning to solve the problem. Cc: Gerd Hoffmann <kraxel@redhat.com> Cc: David Laight <David.Laight@aculab.com> Cc: stable@vger.kernel.org Fixes: 306c54d0 ("usb: hcd: Try MSI interrupts on PCI devices") Signed-off-by: Guenter Roeck <linux@roeck-us.net> Reviewed-by: Alan Stern <stern@rowland.harvard.edu> Reviewed-by: Gerd Hoffmann <kraxel@redhat.com> Link: https://lore.kernel.org/r/20240429154010.1507366-1-linux@roeck-us.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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