From 300871cd963e24a68aaa9b762f4a10403697d9be Mon Sep 17 00:00:00 2001 From: Laurent Pinchart Date: Tue, 12 Jun 2007 21:47:17 +0200 Subject: [PATCH] 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 Acked-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- drivers/usb/core/config.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/usb/core/config.c b/drivers/usb/core/config.c index 9152e12dcf7..5e113db41b5 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 */ -- 2.41.0