Remove wrongly applied upper limit on the interrupt transfer interval for the
low speed devices (not much of an error per se, according to the USB specs)...
Signed-off-by: Sergei Shtylyov <sshtylyov@xxxxxxxxxxxxx>
---
The patch is against the recent Linus' kernel.
drivers/usb/musb/musb_host.c | 18 ++++++++++--------
1 files changed, 10 insertions(+), 8 deletions(-)
Index: linux-2.6/drivers/usb/musb/musb_host.c
===================================================================
--- linux-2.6.orig/drivers/usb/musb/musb_host.c
+++ linux-2.6/drivers/usb/musb/musb_host.c
@@ -1857,19 +1857,21 @@ static int musb_urb_enqueue(
}
qh->type_reg = type_reg;
- /* precompute rxinterval/txinterval register */
- interval = min((u8)16, epd->bInterval); /* log encoding */
+ /* Precompute RXINTERVAL/TXINTERVAL register */
switch (qh->type) {
case USB_ENDPOINT_XFER_INT:
- /* fullspeed uses linear encoding */
- if (USB_SPEED_FULL == urb->dev->speed) {
- interval = epd->bInterval;
- if (!interval)
- interval = 1;
+ /*
+ * Full/low speeds use the linear encoding,
+ * high speed uses the logarithmic encoding.
+ */
+ if (urb->dev->speed <= USB_SPEED_FULL) {
+ interval = max_t(u8, epd->bInterval, 1);
+ break;
}
/* FALLTHROUGH */
case USB_ENDPOINT_XFER_ISOC:
- /* iso always uses log encoding */
+ /* ISO always uses logarithmic encoding */
+ interval = min_t(u8, epd->bInterval, 16);
break;
default:
/* REVISIT we actually want to use NAK limits, hinting to the
--
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