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usb: ohci: Prevent missed ohci interrupts 

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 0b60557230 ("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: 306c54d0ed ("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>
This commit is contained in:
Guenter Roeck 2024-04-29 08:40:10 -07:00 committed by Greg Kroah-Hartman
parent f2004e82ab
commit fe81f35484
1 changed files with 8 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
drivers/usb/host/ohci-hcd.c
View File

@ -888,6 +888,7 @@ static irqreturn_t ohci_irq (struct usb_hcd *hcd)
/* Check for an all 1's result which is a typical consequence
* of dead, unclocked, or unplugged (CardBus...) devices
*/
again:
if (ints == ~(u32)0) {
ohci->rh_state = OHCI_RH_HALTED;
ohci_dbg (ohci, "device removed!\n");
@ -982,6 +983,13 @@ static irqreturn_t ohci_irq (struct usb_hcd *hcd)
}
spin_unlock(&ohci->lock);
/* repeat until all enabled interrupts are handled */
if (ohci->rh_state != OHCI_RH_HALTED) {
ints = ohci_readl(ohci, &regs->intrstatus);
if (ints && (ints & ohci_readl(ohci, &regs->intrenable)))
goto again;
}
return IRQ_HANDLED;
}