On 13.1.2020 11.10, Kai-Heng Feng wrote:
On Fri, Jan 10, 2020 at 5:33 PM Mathias Nyman
<mathias.nyman@xxxxxxxxxxxxxxx> wrote:
@@ -1316,9 +1317,17 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
msleep(20); /* wait device to enter */
spin_lock_irqsave(&xhci->lock, flags);
- temp = readl(ports[wIndex]->addr);
- if (link_state == USB_SS_PORT_LS_U3)
+ if (link_state == USB_SS_PORT_LS_U3) {
+ retval = xhci_handshake(ports[wIndex]->addr, PORT_PLS_MASK, XDEV_U3, 80 * 1000);
+ if (retval)
+ xhci_dbg(xhci, "polling XDEV_U3 on port %d-%d timeout\n", hcd->self.busnum, wIndex + 1);
In worst case we are busylooping for 80ms here, keeping the cpu busy.
It should be ok to sleep here, so how about just reading the register
every 10ms max 10 times, sleeping in between.
Ok. Is the polling safe outside of spin_lock_irqsave()?
Should be, we only read one 32 bit register, and we anyway used to release
and re-acquire the lock right before this anyway.
-Mathias
