From 96044694b8511bc2b04df0776b4ba295cfe005c0 Mon Sep 17 00:00:00 2001 From: Mathias Nyman Date: Thu, 11 Sep 2014 13:55:50 +0300 Subject: [PATCH] xhci: fix oops when xhci resumes from hibernate with hw lpm capable devices Resuming from hibernate (S4) will restart and re-initialize xHC. The device contexts are freed and will be re-allocated later during device reset. Usb core will disable link pm in device resume before device reset, which will try to change the max exit latency, accessing the device contexts before they are re-allocated. There is no need to zero (disable) the max exit latency when disabling hw lpm for a freshly re-initialized xHC. So check that device context exists before doing anything. The max exit latency will be set again after device reset when usb core enables the link pm. Reported-by: Imre Deak Tested-by: Imre Deak Cc: stable Signed-off-by: Mathias Nyman Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/xhci.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c index c020b094fe7d..c4a8fca8ae93 100644 --- a/drivers/usb/host/xhci.c +++ b/drivers/usb/host/xhci.c @@ -3971,13 +3971,21 @@ static int __maybe_unused xhci_change_max_exit_latency(struct xhci_hcd *xhci, int ret; spin_lock_irqsave(&xhci->lock, flags); - if (max_exit_latency == xhci->devs[udev->slot_id]->current_mel) { + + virt_dev = xhci->devs[udev->slot_id]; + + /* + * virt_dev might not exists yet if xHC resumed from hibernate (S4) and + * xHC was re-initialized. Exit latency will be set later after + * hub_port_finish_reset() is done and xhci->devs[] are re-allocated + */ + + if (!virt_dev || max_exit_latency == virt_dev->current_mel) { spin_unlock_irqrestore(&xhci->lock, flags); return 0; } /* Attempt to issue an Evaluate Context command to change the MEL. */ - virt_dev = xhci->devs[udev->slot_id]; command = xhci->lpm_command; ctrl_ctx = xhci_get_input_control_ctx(xhci, command->in_ctx); if (!ctrl_ctx) { -- 2.20.1