Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932667Ab1DZVYC (ORCPT ); Tue, 26 Apr 2011 17:24:02 -0400 Received: from mga09.intel.com ([134.134.136.24]:61258 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932423Ab1DZVOr (ORCPT ); Tue, 26 Apr 2011 17:14:47 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.64,270,1301900400"; d="scan'208";a="738831918" From: Andi Kleen References: <20110426212.641772347@firstfloor.org> In-Reply-To: <20110426212.641772347@firstfloor.org> To: dtor@vmware.com, micah@vmware.com, sarah.a.sharp@linux.intel.com, gregkh@suse.de, ak@linux.intel.com, linux-kernel@vger.kernel.org, stable@kernel.org, tim.bird@am.sony.com Subject: [PATCH] [77/106] USB: xhci - fix math in xhci_get_endpoint_interval() Message-Id: <20110426211358.C58BB3E1886@tassilo.jf.intel.com> Date: Tue, 26 Apr 2011 14:13:58 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4854 Lines: 148 2.6.35-longterm review patch. If anyone has any objections, please let me know. ------------------ From: Dmitry Torokhov commit dfa49c4ad120a784ef1ff0717168aa79f55a483a upstream. 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 Signed-off-by: Dmitry Torokhov Signed-off-by: Sarah Sharp Signed-off-by: Greg Kroah-Hartman Signed-off-by: Andi Kleen --- drivers/usb/host/xhci-mem.c | 85 ++++++++++++++++++++++++++++++++------------ 1 file changed, 62 insertions(+), 23 deletions(-) Index: linux-2.6.35.y/drivers/usb/host/xhci-mem.c =================================================================== --- linux-2.6.35.y.orig/drivers/usb/host/xhci-mem.c +++ linux-2.6.35.y/drivers/usb/host/xhci-mem.c @@ -961,6 +961,47 @@ int xhci_setup_addressable_virt_dev(stru 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 @@ -978,43 +1019,35 @@ static inline unsigned int xhci_get_endp 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: -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/