USB: hcd-pci: Fully suspend across freeze/thaw cycle
authorEvan Green <evgreen@chromium.org>
Thu, 21 Apr 2022 17:39:27 +0000 (10:39 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sat, 23 Apr 2022 08:33:53 +0000 (10:33 +0200)
commit63acaa8e9c65dc34dc249440216f8e977f5d2748
tree70f8767f7db0e7a69238ee6ed3b468ee1f007833
parent9671d55037065e9b83f84f1943bf65fc31036439
USB: hcd-pci: Fully suspend across freeze/thaw cycle

The documentation for the freeze() method says that it "should quiesce
the device so that it doesn't generate IRQs or DMA". The unspoken
consequence of not doing this is that MSIs aimed at non-boot CPUs may
get fully lost if they're sent during the period where the target CPU is
offline.

The current callbacks for USB HCD do not fully quiesce interrupts,
specifically on XHCI. Change to use the full suspend/resume flow for
freeze/thaw to ensure interrupts are fully quiesced. This fixes issues
where USB devices fail to thaw during hibernation because XHCI misses
its interrupt and cannot recover.

Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Evan Green <evgreen@chromium.org>
Link: https://lore.kernel.org/r/20220421103751.v3.2.I8226c7fdae88329ef70957b96a39b346c69a914e@changeid
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/usb/core/hcd-pci.c