diff options
| author | Laurent Pinchart | 2007-06-12 21:47:17 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman | 2007-07-12 16:34:37 -0700 |
| commit | 300871cd963e24a68aaa9b762f4a10403697d9be (patch) | |
| tree | 2ef076a36b077e15a7a6d65a32703c89685bbcfa /drivers/usb | |
| parent | 87d093e25d73249ae92b28ae88db92eaea7df70f (diff) | |
USB: Fix up full-speed bInterval values in high-speed interrupt descriptor
Many device manufacturers are using full-speed bInterval values in high-speed
interrupt endpoint descriptors. If the bInterval value is greater than 16,
assume the device uses full-speed descriptors and fix the value accordingly.
Signed-off-by: Laurent Pinchart <laurent.pinchart@skynet.be>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb')
| -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 9152e12dcf71..5e113db41b59 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 */ |