From 9a355f7cab321c8f700d367b5b663a7364c6e19f Mon Sep 17 00:00:00 2001 From: Sarah Sharp Date: Fri, 13 May 2011 13:10:01 -0700 Subject: [PATCH] xhci: Fix full speed bInterval encoding. commit b513d44751bfb609a3c20463f764c8ce822d63e9 upstream. Dmitry's patch dfa49c4ad120a784ef1ff0717168aa79f55a483a USB: xhci - fix math in xhci_get_endpoint_interval() introduced a bug. The USB 2.0 spec says that full speed isochronous endpoints' bInterval must be decoded as an exponent to a power of two (e.g. interval = 2^(bInterval - 1)). Full speed interrupt endpoints, on the other hand, don't use exponents, and the interval in frames is encoded straight into bInterval. Dmitry's patch was supposed to fix up the full speed isochronous to parse bInterval as an exponent, but instead it changed the *interrupt* endpoint bInterval decoding. The isochronous endpoint encoding was the same. This caused full speed devices with interrupt endpoints (including mice, hubs, and USB to ethernet devices) to fail under NEC 0.96 xHCI host controllers: [ 100.909818] xhci_hcd 0000:06:00.0: add ep 0x83, slot id 1, new drop flags = 0x0, new add flags = 0x99, new slot info = 0x38100000 [ 100.909821] xhci_hcd 0000:06:00.0: xhci_check_bandwidth called for udev ffff88011f0ea000 ... [ 100.910187] xhci_hcd 0000:06:00.0: ERROR: unexpected command completion code 0x11. [ 100.910190] xhci_hcd 0000:06:00.0: xhci_reset_bandwidth called for udev ffff88011f0ea000 When the interrupt endpoint was added and a Configure Endpoint command was issued to the host, the host controller would return a very odd error message (0x11 means "Slot Not Enabled", which isn't true because the slot was enabled). Probably the host controller was getting very confused with the bad encoding. Signed-off-by: Sarah Sharp Cc: Dmitry Torokhov Reported-by: Thomas Lindroth Tested-by: Thomas Lindroth Signed-off-by: Greg Kroah-Hartman Signed-off-by: Andi Kleen --- drivers/usb/host/xhci-mem.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index 7ddb69f3038f..fb0a073470d7 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -1034,12 +1034,12 @@ static inline unsigned int xhci_get_endpoint_interval(struct usb_device *udev, * nearest power of 2. */ case USB_SPEED_FULL: - if (usb_endpoint_xfer_int(&ep->desc)) { + if (usb_endpoint_xfer_isoc(&ep->desc)) { interval = xhci_parse_exponent_interval(udev, ep); break; } /* - * Fall through for isochronous endpoint interval decoding + * Fall through for interrupt endpoint interval decoding * since it uses the same rules as low speed interrupt * endpoints. */ -- 2.39.2