USB: work around for EHCI with quirky periodic schedules

[pandora-kernel.git] / drivers / usb / host / ehci-sched.c

diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index b25cdea..a5535b5 100644 (file)
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -475,6 +475,8 @@ static int enable_periodic (struct ehci_hcd *ehci)
        /* make sure ehci_work scans these */
        ehci->next_uframe = ehci_readl(ehci, &ehci->regs->frame_index)
                % (ehci->periodic_size << 3);
+       if (unlikely(ehci->broken_periodic))
+               ehci->last_periodic_enable = ktime_get_real();
        return 0;
 }
 
@@ -486,6 +488,16 @@ static int disable_periodic (struct ehci_hcd *ehci)
        if (--ehci->periodic_sched)
                return 0;
 
+       if (unlikely(ehci->broken_periodic)) {
+               /* delay experimentally determined */
+               ktime_t safe = ktime_add_us(ehci->last_periodic_enable, 1000);
+               ktime_t now = ktime_get_real();
+               s64 delay = ktime_us_delta(safe, now);
+
+               if (unlikely(delay > 0))
+                       udelay(delay);
+       }
+
        /* did setting PSE not take effect yet?
         * takes effect only at frame boundaries...
         */