From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758627Ab2CMAWf (ORCPT ); Mon, 12 Mar 2012 20:22:35 -0400 Received: from mail.windriver.com ([147.11.1.11]:47729 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758255Ab2CMAWd (ORCPT ); Mon, 12 Mar 2012 20:22:33 -0400 From: Paul Gortmaker To: stable@kernel.org, linux-kernel@vger.kernel.org Cc: stable-review@kernel.org, Dmitry Torokhov , Sarah Sharp , Paul Gortmaker Subject: [34-longterm 077/196] USB: xhci - fix math in xhci_get_endpoint_interval() Date: Mon, 12 Mar 2012 20:19:50 -0400 Message-Id: <1331598109-31424-32-git-send-email-paul.gortmaker@windriver.com> X-Mailer: git-send-email 1.7.9.3 In-Reply-To: <1331598109-31424-1-git-send-email-paul.gortmaker@windriver.com> References: <1331597724-31358-1-git-send-email-paul.gortmaker@windriver.com> <1331598109-31424-1-git-send-email-paul.gortmaker@windriver.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Dmitry Torokhov ------------------- This is a commit scheduled for the next v2.6.34 longterm release. If you see a problem with using this for longterm, please comment. ------------------- 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: Paul Gortmaker --- drivers/usb/host/xhci-mem.c | 90 +++++++++++++++++++++++++++++-------------- 1 file changed, 62 insertions(+), 28 deletions(-) diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index e560dd4..e1dbcc2 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -520,6 +520,47 @@ 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 @@ -537,45 +578,38 @@ static inline 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(); } -- 1.7.9.3