Commit 904df64a authored Aug 21, 2020 by Kai-Heng Feng Committed by Greg Kroah-Hartman Aug 23, 2020

xhci: Do warm-reset when both CAS and XDEV_RESUME are set



Sometimes re-plugging a USB device during system sleep renders the device
useless:
[  173.418345] xhci_hcd 0000:00:14.0: Get port status 2-4 read: 0x14203e2, return 0x10262
...
[  176.496485] usb 2-4: Waited 2000ms for CONNECT
[  176.496781] usb usb2-port4: status 0000.0262 after resume, -19
[  176.497103] usb 2-4: can't resume, status -19
[  176.497438] usb usb2-port4: logical disconnect

Because PLS equals to XDEV_RESUME, xHCI driver reports U3 to usbcore,
despite of CAS bit is flagged.

So proritize CAS over XDEV_RESUME to let usbcore handle warm-reset for
the port.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20200821091549.20556-3-mathias.nyman@linux.intel.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent 0077b1b2

drivers/usb/host/xhci-hub.c

+10 −9

Original line number	Diff line number	Diff line
		@@ -740,15 +740,6 @@ static void xhci_hub_report_usb3_link_state(struct xhci_hcd *xhci,
		{
		u32 pls = status_reg & PORT_PLS_MASK;

		/* resume state is a xHCI internal state.
		* Do not report it to usb core, instead, pretend to be U3,
		* thus usb core knows it's not ready for transfer
		*/
		if (pls == XDEV_RESUME) {
		*status \|= USB_SS_PORT_LS_U3;
		return;
		}

		/* When the CAS bit is set then warm reset
		* should be performed on port
		*/
		@@ -770,6 +761,16 @@ static void xhci_hub_report_usb3_link_state(struct xhci_hcd *xhci,
		*/
		pls \|= USB_PORT_STAT_CONNECTION;
		} else {
		/*
		* Resume state is an xHCI internal state. Do not report it to
		* usb core, instead, pretend to be U3, thus usb core knows
		* it's not ready for transfer.
		*/
		if (pls == XDEV_RESUME) {
		*status \|= USB_SS_PORT_LS_U3;
		return;
		}

		/*
		* If CAS bit isn't set but the Port is already at
		* Compliance Mode, fake a connection so the USB core

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