Commit ff9a09b3 authored by Niklas Neronin's avatar Niklas Neronin Committed by Greg Kroah-Hartman
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usb: xhci: fix host not responding after suspend and resume 

Partially revert commit e1db856b ("usb: xhci: remove '0' write to
write-1-to-clear register") because the patch cleared the Interrupt Pending
bit during interrupt enabling and disabling. The Interrupt Pending bit
should only be cleared when the driver has handled the interrupt.

Ideally, all interrupts should be handled before disabling the interrupt;
consequently, no interrupt should be pending when enabling the interrupt.
For this reason, keep the debug message informing if an interrupt is still
pending when an interrupt is disabled.

Because the Interrupt Pending bit is write-1-to-clear, writing '0' to it
ensures that the state does not change.

Link: https://lore.kernel.org/linux-usb/20250818231103.672ec7ed@foxbook
Fixes: e1db856b ("usb: xhci: remove '0' write to write-1-to-clear register")
Closes: https://bbs.archlinux.org/viewtopic.php?id=307641


cc: stable@vger.kernel.org # 6.16+
Signed-off-by: default avatarNiklas Neronin <niklas.neronin@linux.intel.com>
Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20250819125844.2042452-3-mathias.nyman@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 2eb03376

drivers/usb/host/xhci.c

+2 −0
Original line number Diff line number Diff line
@@ -309,6 +309,7 @@ int xhci_enable_interrupter(struct xhci_interrupter *ir) 
		return -EINVAL;



	iman = readl(&ir->ir_set->iman);

	iman &= ~IMAN_IP;

	iman |= IMAN_IE;

	writel(iman, &ir->ir_set->iman);
@@ -325,6 +326,7 @@ int xhci_disable_interrupter(struct xhci_hcd *xhci, struct xhci_interrupter *ir) 
		return -EINVAL;



	iman = readl(&ir->ir_set->iman);

	iman &= ~IMAN_IP;

	iman &= ~IMAN_IE;

	writel(iman, &ir->ir_set->iman);