Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161314AbaGRNX6 (ORCPT ); Fri, 18 Jul 2014 09:23:58 -0400 Received: from bband-dyn38.178-41-141.t-com.sk ([178.41.141.38]:17946 "EHLO ip4-83-240-18-248.cust.nbox.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1030805AbaGRNSK (ORCPT ); Fri, 18 Jul 2014 09:18:10 -0400 From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Mathias Nyman , Jiri Slaby Subject: [PATCH 3.12 064/170] xhci: correct burst count field for isoc transfers on 1.0 xhci hosts Date: Fri, 18 Jul 2014 14:11:09 +0200 Message-Id: <02fe41346ccc70b4d4b487072c644e3483d51a88.1405685481.git.jslaby@suse.cz> X-Mailer: git-send-email 2.0.0 In-Reply-To: <48e8cad86bb1241c08bdaa80db022c25068ff8e0.1405685481.git.jslaby@suse.cz> References: <48e8cad86bb1241c08bdaa80db022c25068ff8e0.1405685481.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Mathias Nyman 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 3213b151387df0b95f4eada104f68eb1c1409cb3 upstream. The transfer burst count (TBC) field in xhci 1.0 hosts should be set to the number of bursts needed to transfer all packets in a isoc TD. Supported values are 0-2 (1 to 3 bursts per service interval). Formula for TBC calculation is given in xhci spec section 4.11.2.3: TBC = roundup( Transfer Descriptor Packet Count / Max Burst Size +1 ) - 1 This patch should be applied to stable kernels since 3.0 that contain the commit 5cd43e33b9519143f06f507dd7cbee6b7a621885 "xhci 1.0: Set transfer burst count field." Suggested-by: ShiChun Ma Signed-off-by: Mathias Nyman Signed-off-by: Jiri Slaby Signed-off-by: Jiri Slaby --- drivers/usb/host/xhci-ring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index 1dbfb52dbcd6..6118e292d5df 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -3633,7 +3633,7 @@ static unsigned int xhci_get_burst_count(struct xhci_hcd *xhci, return 0; max_burst = urb->ep->ss_ep_comp.bMaxBurst; - return roundup(total_packet_count, max_burst + 1) - 1; + return DIV_ROUND_UP(total_packet_count, max_burst + 1) - 1; } /* -- 2.0.0 -- 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/