diff options
| -rw-r--r-- | drivers/usb/host/ehci-sched.c | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c index ebcca970067..88419c6823a 100644 --- a/drivers/usb/host/ehci-sched.c +++ b/drivers/usb/host/ehci-sched.c @@ -707,6 +707,7 @@ iso_stream_init ( } else { u32 addr; int think_time; + int hs_transfers; addr = dev->ttport << 24; if (!ehci_is_TDI(ehci) @@ -719,6 +720,7 @@ iso_stream_init ( think_time = dev->tt ? dev->tt->think_time : 0; stream->tt_usecs = NS_TO_US (think_time + usb_calc_bus_time ( dev->speed, is_input, 1, maxp)); + hs_transfers = max (1u, (maxp + 187) / 188); if (is_input) { u32 tmp; @@ -727,12 +729,11 @@ iso_stream_init ( stream->usecs = HS_USECS_ISO (1); stream->raw_mask = 1; - /* pessimistic c-mask */ - tmp = usb_calc_bus_time (USB_SPEED_FULL, 1, 0, maxp) - / (125 * 1000); - stream->raw_mask |= 3 << (tmp + 9); + /* c-mask as specified in USB 2.0 11.18.4 3.c */ + tmp = (1 << (hs_transfers + 2)) - 1; + stream->raw_mask |= tmp << (8 + 2); } else - stream->raw_mask = smask_out [maxp / 188]; + stream->raw_mask = smask_out [hs_transfers - 1]; bandwidth = stream->usecs + stream->c_usecs; bandwidth /= 1 << (interval + 2); |