Messages in this thread Patch in this message | | | From | Kai-Heng Feng <> | Subject | [PATCH v2] xhci: Set port link to RxDetect if port is not enabled after resume | Date | Wed, 11 Mar 2020 12:04:56 +0800 |
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On Dell TB16, Realtek USB ethernet (r8152) connects to an SMSC hub which then connects to ASMedia xHCI's root hub:
/: Bus 04.Port 1: Dev 1, Class=root_hub, Driver=xhci_hcd/2p, 5000M |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/7p, 5000M |__ Port 2: Dev 3, If 0, Class=Vendor Specific Class, Driver=r8152, 5000M
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 004 Device 002: ID 0424:5537 Standard Microsystems Corp. USB5537B Bus 004 Device 003: ID 0bda:8153 Realtek Semiconductor Corp. RTL8153 Gigabit Ethernet Adapter
The port is disabled after resume: xhci_hcd 0000:3f:00.0: Get port status 4-1 read: 0x280, return 0x280
According to xHCI 4.19.1.2.1, we should set link to RxDetect to transit it from disabled state to disconnected state, which allows the port to be set to U0 and completes the resume process.
My own test shows port can still resume when it's not enabled, as long as its link is in U states. So constrain the new logic only when link is not in any U state.
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com> --- drivers/usb/host/xhci-hub.c | 8 ++++++++ 1 file changed, 8 insertions(+)
diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c index a9c87eb8951e..263f9a9237a1 100644 --- a/drivers/usb/host/xhci-hub.c +++ b/drivers/usb/host/xhci-hub.c @@ -1776,6 +1776,14 @@ int xhci_bus_resume(struct usb_hcd *hcd) clear_bit(port_index, &bus_state->bus_suspended); continue; } + + /* 4.19.1.2.1 */ + if (!(portsc & PORT_PE) && (portsc & PORT_PLS_MASK) > XDEV_U3) { + portsc = xhci_port_state_to_neutral(portsc); + portsc &= ~PORT_PLS_MASK; + portsc |= PORT_LINK_STROBE | XDEV_RXDETECT; + } + /* resume if we suspended the link, and it is still suspended */ if (test_bit(port_index, &bus_state->bus_suspended)) switch (portsc & PORT_PLS_MASK) { -- 2.17.1
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