From: Kai-Heng Feng kai.heng.feng@canonical.com
[ Upstream commit eb002726fac7cefb98ff39ddb89e150a1c24fe85 ]
The xHCI spec doesn't specify the upper bound of U3 transition time. For some devices 20ms is not enough, so we need to make sure the link state is in U3 before further actions.
I've tried to use U3 Entry Capability by setting U3 Entry Enable in config register, however the port change event for U3 transition interrupts the system suspend process.
For now let's use the less ideal method by polling PLS.
[use usleep_range(), and shorten the delay time while polling -Mathias] 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/20200312144517.1593-7-mathias.nyman@linux.intel.co... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/usb/host/xhci-hub.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c index a024230f00e2d..eb4284696f25c 100644 --- a/drivers/usb/host/xhci-hub.c +++ b/drivers/usb/host/xhci-hub.c @@ -1266,7 +1266,16 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue, xhci_set_link_state(xhci, ports[wIndex], link_state);
spin_unlock_irqrestore(&xhci->lock, flags); - msleep(20); /* wait device to enter */ + if (link_state == USB_SS_PORT_LS_U3) { + int retries = 16; + + while (retries--) { + usleep_range(4000, 8000); + temp = readl(ports[wIndex]->addr); + if ((temp & PORT_PLS_MASK) == XDEV_U3) + break; + } + } spin_lock_irqsave(&xhci->lock, flags);
temp = readl(ports[wIndex]->addr);