From 136733d6124a152ed2b61c3d38008c6581fc8685 Mon Sep 17 00:00:00 2001 From: Sergei Shtylyov Date: Sat, 21 Feb 2009 15:31:35 -0800 Subject: [PATCH] USB: musb: use right poll limit for low speed devices Remove wrongly applied upper limit on the interrupt transfer interval for low speed devices (not much of an error per se, according to USB specs). Signed-off-by: Sergei Shtylyov Signed-off-by: David Brownell Signed-off-by: Greg Kroah-Hartman --- drivers/usb/musb/musb_host.c | 18 ++++++++++-------- 1 file changed, 10 insertions(+), 8 deletions(-) diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c index 23d3890fd54..6dbbd0786a6 100644 --- a/drivers/usb/musb/musb_host.c +++ b/drivers/usb/musb/musb_host.c @@ -1863,19 +1863,21 @@ 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