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author | Dmitry Torokhov <dtor@vmware.com> | 2011-03-23 22:41:23 -0700 |
---|---|---|
committer | Sarah Sharp <sarah.a.sharp@linux.intel.com> | 2011-04-13 16:19:48 -0700 |
commit | dfa49c4ad120a784ef1ff0717168aa79f55a483a (patch) | |
tree | d8dc009e82608aa2935d95ab07f50d7d3e3b7d9a /drivers/usb/host | |
parent | 926008c9386dde09b015753b6681c502177baa30 (diff) | |
download | linux-stable-dfa49c4ad120a784ef1ff0717168aa79f55a483a.tar.gz linux-stable-dfa49c4ad120a784ef1ff0717168aa79f55a483a.tar.bz2 linux-stable-dfa49c4ad120a784ef1ff0717168aa79f55a483a.zip |
USB: xhci - fix math in xhci_get_endpoint_interval()
When parsing exponent-expressed intervals we subtract 1 from the
value and then expect it to match with original + 1, which is
highly unlikely, and we end with frequent spew:
usb 3-4: ep 0x83 - rounding interval to 512 microframes
Also, parsing interval for fullspeed isochronous endpoints was
incorrect - according to USB spec they use exponent-based
intervals (but xHCI spec claims frame-based intervals). I trust
USB spec more, especially since USB core agrees with it.
This should be queued for stable kernels back to 2.6.31.
Reviewed-by: Micah Elizabeth Scott <micah@vmware.com>
Signed-off-by: Dmitry Torokhov <dtor@vmware.com>
Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Cc: stable@kernel.org
Diffstat (limited to 'drivers/usb/host')
-rw-r--r-- | drivers/usb/host/xhci-mem.c | 90 |
1 files changed, 62 insertions, 28 deletions
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index 7f56c9b80692..627f3438028c 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -974,6 +974,47 @@ int xhci_setup_addressable_virt_dev(struct xhci_hcd *xhci, struct usb_device *ud return 0; } +/* + * Convert interval expressed as 2^(bInterval - 1) == interval into + * straight exponent value 2^n == interval. + * + */ +static unsigned int xhci_parse_exponent_interval(struct usb_device *udev, + struct usb_host_endpoint *ep) +{ + unsigned int interval; + + interval = clamp_val(ep->desc.bInterval, 1, 16) - 1; + if (interval != ep->desc.bInterval - 1) + dev_warn(&udev->dev, + "ep %#x - rounding interval to %d microframes\n", + ep->desc.bEndpointAddress, + 1 << interval); + + return interval; +} + +/* + * Convert bInterval expressed in frames (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) +{ + unsigned int interval; + + interval = fls(8 * ep->desc.bInterval) - 1; + interval = clamp_val(interval, 3, 10); + if ((1 << interval) != 8 * ep->desc.bInterval) + 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); + + return interval; +} + /* Return the polling or NAK interval. * * The polling interval is expressed in "microframes". If xHCI's Interval field @@ -991,45 +1032,38 @@ static unsigned int xhci_get_endpoint_interval(struct usb_device *udev, case USB_SPEED_HIGH: /* Max NAK rate */ if (usb_endpoint_xfer_control(&ep->desc) || - usb_endpoint_xfer_bulk(&ep->desc)) + usb_endpoint_xfer_bulk(&ep->desc)) { interval = ep->desc.bInterval; + break; + } /* Fall through - SS and HS isoc/int have same decoding */ + case USB_SPEED_SUPER: if (usb_endpoint_xfer_int(&ep->desc) || - usb_endpoint_xfer_isoc(&ep->desc)) { - if (ep->desc.bInterval == 0) - interval = 0; - else - interval = ep->desc.bInterval - 1; - if (interval > 15) - interval = 15; - if (interval != ep->desc.bInterval + 1) - dev_warn(&udev->dev, "ep %#x - rounding interval to %d microframes\n", - ep->desc.bEndpointAddress, 1 << interval); + usb_endpoint_xfer_isoc(&ep->desc)) { + interval = xhci_parse_exponent_interval(udev, ep); } break; - /* Convert bInterval (in 1-255 frames) to microframes and round down to - * nearest power of 2. - */ + case USB_SPEED_FULL: + if (usb_endpoint_xfer_int(&ep->desc)) { + interval = xhci_parse_exponent_interval(udev, ep); + break; + } + /* + * Fall through for isochronous endpoint interval decoding + * since it uses the same rules as low speed interrupt + * endpoints. + */ + case USB_SPEED_LOW: if (usb_endpoint_xfer_int(&ep->desc) || - usb_endpoint_xfer_isoc(&ep->desc)) { - interval = fls(8*ep->desc.bInterval) - 1; - if (interval > 10) - interval = 10; - if (interval < 3) - interval = 3; - if ((1 << interval) != 8*ep->desc.bInterval) - 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); + usb_endpoint_xfer_isoc(&ep->desc)) { + + interval = xhci_parse_frame_interval(udev, ep); } break; + default: BUG(); } |