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authorMathias Nyman <mathias.nyman@linux.intel.com>2018-06-21 16:19:41 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-06-25 16:16:27 +0300
commit229bc19fd7aca4f37964af06e3583c1c8f36b5d6 (patch)
treeba29eec42c20d7627d9006ffb07987ce82382a5a /drivers/usb/host/xhci.h
parent9d1a68c458c71171f8670d7e994ba1d135790fe7 (diff)
downloadlinux-229bc19fd7aca4f37964af06e3583c1c8f36b5d6.tar.xz
xhci: Fix perceived dead host due to runtime suspend race with event handler
Don't rely on event interrupt (EINT) bit alone to detect pending port change in resume. If no change event is detected the host may be suspended again, oterwise roothubs are resumed. There is a lag in xHC setting EINT. If we don't notice the pending change in resume, and the controller is runtime suspeded again, it causes the event handler to assume host is dead as it will fail to read xHC registers once PCI puts the controller to D3 state. [ 268.520969] xhci_hcd: xhci_resume: starting port polling. [ 268.520985] xhci_hcd: xhci_hub_status_data: stopping port polling. [ 268.521030] xhci_hcd: xhci_suspend: stopping port polling. [ 268.521040] xhci_hcd: // Setting command ring address to 0x349bd001 [ 268.521139] xhci_hcd: Port Status Change Event for port 3 [ 268.521149] xhci_hcd: resume root hub [ 268.521163] xhci_hcd: port resume event for port 3 [ 268.521168] xhci_hcd: xHC is not running. [ 268.521174] xhci_hcd: handle_port_status: starting port polling. [ 268.596322] xhci_hcd: xhci_hc_died: xHCI host controller not responding, assume dead The EINT lag is described in a additional note in xhci specs 4.19.2: "Due to internal xHC scheduling and system delays, there will be a lag between a change bit being set and the Port Status Change Event that it generated being written to the Event Ring. If SW reads the PORTSC and sees a change bit set, there is no guarantee that the corresponding Port Status Change Event has already been written into the Event Ring." Cc: <stable@vger.kernel.org> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/host/xhci.h')
-rw-r--r--drivers/usb/host/xhci.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 939e2f86b595..841e89ffe2e9 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -382,6 +382,10 @@ struct xhci_op_regs {
#define PORT_PLC (1 << 22)
/* port configure error change - port failed to configure its link partner */
#define PORT_CEC (1 << 23)
+#define PORT_CHANGE_MASK (PORT_CSC | PORT_PEC | PORT_WRC | PORT_OCC | \
+ PORT_RC | PORT_PLC | PORT_CEC)
+
+
/* Cold Attach Status - xHC can set this bit to report device attached during
* Sx state. Warm port reset should be perfomed to clear this bit and move port
* to connected state.