FEX-Emu/linux
1
0
Fork 0
mirror of https://github.com/FEX-Emu/linux.git synced 2025-02-10 21:35:08 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

xhci: correct burst count field for isoc transfers on 1.0 xhci hosts

Browse Source 
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."

Cc: stable@vger.kernel.org # 3.0
Suggested-by: ShiChun Ma <masc2008@qq.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mathias Nyman 2014-06-24 17:14:41 +03:00 committed by Greg Kroah-Hartman
parent 6fcfb0d682
commit 3213b15138
1 changed files with 1 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/usb/host/xhci-ring.c
View File

@ -3537,7 +3537,7 @@ 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;
}
/*