diff mbox series

[RFT] xhci: track port suspend state correctly in unsuccessful resume cases

Message ID 20230914092724.1469813-1-mathias.nyman@linux.intel.com (mailing list archive)
State Accepted
Commit d7cdfc319b2bcf6899ab0a05eec0958bc802a9a1
Headers show
Series [RFT] xhci: track port suspend state correctly in unsuccessful resume cases | expand

Commit Message

Mathias Nyman Sept. 14, 2023, 9:27 a.m. UTC
xhci-hub.c tracks suspended ports in a suspended_port bitfield.
This is checked when responding to a Get_Status(PORT) request to see if a
port in running U0 state was recently resumed, and adds the required
USB_PORT_STAT_C_SUSPEND change bit in those cases.

The suspended_port bit was left uncleared if a device is disconnected
during suspend. The bit remained set even when a new device was connected
and enumerated. The set bit resulted in a incorrect Get_Status(PORT)
response with a bogus USB_PORT_STAT_C_SUSPEND change
bit set once the new device reached U0 link state.

USB_PORT_STAT_C_SUSPEND change bit is only used for USB2 ports, but
xhci-hub keeps track of both USB2 and USB3 suspended ports.

Reported-by: Wesley Cheng <quic_wcheng@quicinc.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
---
 drivers/usb/host/xhci-hub.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

Comments

Wesley Cheng Sept. 15, 2023, 12:34 a.m. UTC | #1
Hi Mathias,

On 9/14/2023 2:27 AM, Mathias Nyman wrote:
> xhci-hub.c tracks suspended ports in a suspended_port bitfield.
> This is checked when responding to a Get_Status(PORT) request to see if a
> port in running U0 state was recently resumed, and adds the required
> USB_PORT_STAT_C_SUSPEND change bit in those cases.
> 
> The suspended_port bit was left uncleared if a device is disconnected
> during suspend. The bit remained set even when a new device was connected
> and enumerated. The set bit resulted in a incorrect Get_Status(PORT)
> response with a bogus USB_PORT_STAT_C_SUSPEND change
> bit set once the new device reached U0 link state.
> 
> USB_PORT_STAT_C_SUSPEND change bit is only used for USB2 ports, but
> xhci-hub keeps track of both USB2 and USB3 suspended ports.
> 

Thanks for looking at this change.  Tested it on my environment and it 
looks good to me:

//Disconnect while bus is suspended (before get status)
msm-dwc3 a600000.ssusb: DWC3 exited from low power mode
xhci_resume: usb3 suspended_ports = 0, bus_suspended = 0
xhci_resume: usb2 suspended_ports = 1, bus_suspended = 0
usb 1-1: USB disconnect, device number 2
msm-dwc3 a600000.ssusb: could not transition HS PHY to L2
msm-dwc3 a600000.ssusb: DWC3 in low power mode

//Plug in after disconnect
msm-dwc3 a600000.ssusb: DWC3 exited from low power mode
xhci_resume: usb3 suspended_ports = 0, bus_suspended = 0
xhci_resume: usb2 suspended_ports = 0, bus_suspended = 0
usb 1-1: new full-speed USB device number 3 using xhci-hcd
...
msm-dwc3 a600000.ssusb: could not transition HS PHY to L2
msm-dwc3 a600000.ssusb: DWC3 in low power mode

//Remote wakeup
msm-dwc3 a600000.ssusb: DWC3 exited from low power mode
xhci_resume: usb3 suspended_ports = 0, bus_suspended = 0
xhci_resume: usb2 suspended_ports = 1, bus_suspended = 0
plantronics 0003:047F:C025.0002: intr, xhci-hcd.2.auto-1/input3, status -2
msm-dwc3 a600000.ssusb: could not transition HS PHY to L2
msm-dwc3 a600000.ssusb: DWC3 in low power mode

Will update my change ([1]) to include testing for the suspended_ports 
for if a device is connected (and suspended) while running xhci_resume()

Thanks
Wesley Cheng

[1] 
https://lore.kernel.org/linux-usb/20230901001518.25403-1-quic_wcheng@quicinc.com/
diff mbox series

Patch

diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 0054d02239e2..0df5d807a77e 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -1062,19 +1062,19 @@  static void xhci_get_usb3_port_status(struct xhci_port *port, u32 *status,
 		*status |= USB_PORT_STAT_C_CONFIG_ERROR << 16;
 
 	/* USB3 specific wPortStatus bits */
-	if (portsc & PORT_POWER) {
+	if (portsc & PORT_POWER)
 		*status |= USB_SS_PORT_STAT_POWER;
-		/* link state handling */
-		if (link_state == XDEV_U0)
-			bus_state->suspended_ports &= ~(1 << portnum);
-	}
 
-	/* remote wake resume signaling complete */
-	if (bus_state->port_remote_wakeup & (1 << portnum) &&
+	/* no longer suspended or resuming */
+	if (link_state != XDEV_U3 &&
 	    link_state != XDEV_RESUME &&
 	    link_state != XDEV_RECOVERY) {
-		bus_state->port_remote_wakeup &= ~(1 << portnum);
-		usb_hcd_end_port_resume(&hcd->self, portnum);
+		/* remote wake resume signaling complete */
+		if (bus_state->port_remote_wakeup & (1 << portnum)) {
+			bus_state->port_remote_wakeup &= ~(1 << portnum);
+			usb_hcd_end_port_resume(&hcd->self, portnum);
+		}
+		bus_state->suspended_ports &= ~(1 << portnum);
 	}
 
 	xhci_hub_report_usb3_link_state(xhci, status, portsc);
@@ -1131,6 +1131,7 @@  static void xhci_get_usb2_port_status(struct xhci_port *port, u32 *status,
 			usb_hcd_end_port_resume(&port->rhub->hcd->self, portnum);
 		}
 		port->rexit_active = 0;
+		bus_state->suspended_ports &= ~(1 << portnum);
 	}
 }