The xHCI 0.96 spec says that HS bulk and control endpoint NAK rate must be encoded as an exponent of two number of microframes. The endpoint descriptor has the NAK rate encoded in number of microframes. We were just copying the value from the endpoint descriptor into the endpoint context interval field, which was not correct. This lead to the VIA host rejecting the add of a bulk OUT endpoint from any USB 2.0 mass storage device. The fix is to use the correct encoding. Refactor the code to convert number of frames to an exponential number of microframes, and make sure we convert the number of microframes in HS bulk and control endpoints to an exponent. Signed-off-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx> Reported-by: Felipe Contreras <felipe.contreras@xxxxxxxxx> Suggested-by: Andiry Xu <andiry.xu@xxxxxxx> --- Hi Felipe, Can you test this bug fix and see if it makes USB 2.0 mass storage devices work under your VIA host? Send me the dmesg if it doesn't. Thanks, Sarah Sharp drivers/usb/host/xhci-mem.c | 32 ++++++++++++++++++++++++-------- 1 files changed, 24 insertions(+), 8 deletions(-) diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index 36cbe22..383fc85 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -1126,26 +1126,42 @@ static unsigned int xhci_parse_exponent_interval(struct usb_device *udev, } /* - * Convert bInterval expressed in frames (in 1-255 range) to exponent of + * Convert bInterval expressed in microframes (in 1-255 range) to exponent of * microframes, rounded down to nearest power of 2. */ -static unsigned int xhci_parse_frame_interval(struct usb_device *udev, - struct usb_host_endpoint *ep) +static unsigned int xhci_microframes_to_exponent(struct usb_device *udev, + struct usb_host_endpoint *ep, unsigned int desc_interval, + unsigned int min_exponent, unsigned int max_exponent) { unsigned int interval; - interval = fls(8 * ep->desc.bInterval) - 1; - interval = clamp_val(interval, 3, 10); - if ((1 << interval) != 8 * ep->desc.bInterval) + interval = fls(desc_interval) - 1; + interval = clamp_val(interval, min_exponent, max_exponent); + if ((1 << interval) != desc_interval) dev_warn(&udev->dev, "ep %#x - rounding interval to %d microframes, ep desc says %d microframes\n", ep->desc.bEndpointAddress, 1 << interval, - 8 * ep->desc.bInterval); + desc_interval); return interval; } +static unsigned int xhci_parse_microframe_interval(struct usb_device *udev, + struct usb_host_endpoint *ep) +{ + return xhci_microframes_to_exponent(udev, ep, + ep->desc.bInterval, 0, 15); +} + + +static unsigned int xhci_parse_frame_interval(struct usb_device *udev, + struct usb_host_endpoint *ep) +{ + return xhci_microframes_to_exponent(udev, ep, + ep->desc.bInterval * 8, 3, 10); +} + /* Return the polling or NAK interval. * * The polling interval is expressed in "microframes". If xHCI's Interval field @@ -1164,7 +1180,7 @@ static unsigned int xhci_get_endpoint_interval(struct usb_device *udev, /* Max NAK rate */ if (usb_endpoint_xfer_control(&ep->desc) || usb_endpoint_xfer_bulk(&ep->desc)) { - interval = ep->desc.bInterval; + interval = xhci_parse_microframe_interval(udev, ep); break; } /* Fall through - SS and HS isoc/int have same decoding */ -- 1.7.9 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html