This is a note to let you know that I've just added the patch titled xhci: correct burst count field for isoc transfers on 1.0 xhci hosts to the 3.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: xhci-correct-burst-count-field-for-isoc-transfers-on-1.0-xhci-hosts.patch and it can be found in the queue-3.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 3213b151387df0b95f4eada104f68eb1c1409cb3 Mon Sep 17 00:00:00 2001 From: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> Date: Tue, 24 Jun 2014 17:14:41 +0300 Subject: xhci: correct burst count field for isoc transfers on 1.0 xhci hosts From: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> 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 <masc2008@xxxxxx> Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/usb/host/xhci-ring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -3666,7 +3666,7 @@ static unsigned int xhci_get_burst_count 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; } /* Patches currently in stable-queue which might be from mathias.nyman@xxxxxxxxxxxxxxx are queue-3.14/xhci-use-correct-slot-id-when-handling-a-reset-device-command.patch queue-3.14/xhci-fix-runtime-suspended-xhci-from-blocking-system-suspend.patch queue-3.14/xhci-correct-burst-count-field-for-isoc-transfers-on-1.0-xhci-hosts.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html