From fe81f354841641c7f71163b84912b25c169ed8ec Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Mon, 29 Apr 2024 08:40:10 -0700 Subject: [PATCH] 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 0b60557230ad ("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 Cc: David Laight Cc: stable@vger.kernel.org Fixes: 306c54d0edb6 ("usb: hcd: Try MSI interrupts on PCI devices") Signed-off-by: Guenter Roeck Reviewed-by: Alan Stern Reviewed-by: Gerd Hoffmann Link: https://lore.kernel.org/r/20240429154010.1507366-1-linux@roeck-us.net Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/ohci-hcd.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c index 4f9982ecfb58..5cec7640e913 100644 --- a/drivers/usb/host/ohci-hcd.c +++ b/drivers/usb/host/ohci-hcd.c @@ -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, ®s->intrstatus); + if (ints && (ints & ohci_readl(ohci, ®s->intrenable))) + goto again; + } + return IRQ_HANDLED; }