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

Commit d0d3435b authored by Hans de Goede's avatar Hans de Goede Committed by Mauro Carvalho Chehab
Browse files

[media] gspca - main: Correct use of interval in bandwidth calculation 



The calculated bandwidth should not be multiplied by the interval, but be
divided by it. Also bInterbval should be interpreted as a power of 2
for isochronous endpoints.

Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarJean-François Moine <moinejf@free.fr>
Signed-off-by: default avatarMauro Carvalho Chehab <mchehab@redhat.com>
parent 66957b86

drivers/media/video/gspca/gspca.c

+6 −1
Original line number Diff line number Diff line
@@ -698,12 +698,17 @@ static int build_isoc_ep_tb(struct gspca_dev *gspca_dev, 
				      USB_ENDPOINT_XFER_ISOC);

			if (ep == NULL)

				continue;

			if (ep->desc.bInterval == 0) {

				pr_err("alt %d iso endp with 0 interval\n", j);

				continue;

			}

			psize = le16_to_cpu(ep->desc.wMaxPacketSize);

			psize = (psize & 0x07ff) * (1 + ((psize >> 11) & 3));

			bandwidth = psize * ep->desc.bInterval * 1000;

			bandwidth = psize * 1000;

			if (gspca_dev->dev->speed == USB_SPEED_HIGH

			 || gspca_dev->dev->speed == USB_SPEED_SUPER)

				bandwidth *= 8;

			bandwidth /= 1 << (ep->desc.bInterval - 1);

			if (bandwidth <= last_bw)

				continue;

			if (bandwidth < ep_tb->bandwidth) {