Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 300871cd authored by Laurent Pinchart's avatar Laurent Pinchart Committed by Greg Kroah-Hartman
Browse files

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: default avatarLaurent Pinchart <laurent.pinchart@skynet.be>
Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 87d093e2

drivers/usb/core/config.c

+9 −3
Original line number Diff line number Diff line
@@ -85,14 +85,20 @@ 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:

			/* 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;