xhci: workaround for hosts missing CAS bit
If a device is unplugged and replugged during Sx system suspend
some Intel xHC hosts will overwrite the CAS (Cold attach status) flag
and no device connection is noticed in resume.
A device in this state can be identified in resume if its link state
is in polling or compliance mode, and the current connect status is 0.
A device in this state needs to be warm reset.
Intel 100/c230 series PCH specification update Doc #332692-006 Errata #8
Observed on Cherryview and Apollolake as they go into compliance mode
if LFPS times out during polling, and re-plugged devices are not
discovered at resume.
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index b2c1dc5..f945380 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -314,6 +314,8 @@ struct xhci_op_regs {
#define XDEV_U2 (0x2 << 5)
#define XDEV_U3 (0x3 << 5)
#define XDEV_INACTIVE (0x6 << 5)
+#define XDEV_POLLING (0x7 << 5)
+#define XDEV_COMP_MODE (0xa << 5)
#define XDEV_RESUME (0xf << 5)
/* true: port has power (see HCC_PPC) */
#define PORT_POWER (1 << 9)
@@ -1653,6 +1655,7 @@ struct xhci_hcd {
#define XHCI_MTK_HOST (1 << 21)
#define XHCI_SSIC_PORT_UNUSED (1 << 22)
#define XHCI_NO_64BIT_SUPPORT (1 << 23)
+#define XHCI_MISSING_CAS (1 << 24)
unsigned int num_active_eps;
unsigned int limit_active_eps;
/* There are two roothubs to keep track of bus suspend info for */