diff options
| -rw-r--r-- | drivers/usb/core/config.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c index 9152e12..5e113db 100644 --- a/drivers/usb/core/config.c +++ b/drivers/usb/core/config.c @@ -85,15 +85,21 @@ static int usb_parse_endpoint(struct device *ddev, int cfgno, int inum, memcpy(&endpoint->desc, d, n); INIT_LIST_HEAD(&endpoint->urb_list); - /* If the bInterval value is outside the legal range, - * set it to a default value: 32 ms */ + /* Fix up bInterval values outside the legal range. Use 32 ms if no + * proper value can be guessed. */ i = 0; /* i = min, j = max, n = default */ j = 255; if (usb_endpoint_xfer_int(d)) { i = 1; switch (to_usb_device(ddev)->speed) { case USB_SPEED_HIGH: - n = 9; /* 32 ms = 2^(9-1) uframes */ + /* Many device manufacturers are using full-speed + * bInterval values in high-speed interrupt endpoint + * descriptors. Try to fix those and fall back to a + * 32 ms default value otherwise. */ + n = fls(d->bInterval*8); + if (n == 0) + n = 9; /* 32 ms = 2^(9-1) uframes */ j = 16; break; default: /* USB_SPEED_FULL or _LOW */ |