If URB_ZERO_PACKET is set then make sure that the last usb message sent isn't a full sized one. A partial transfer is needed to terminate variable length bulk output (eg ethernet frames).
URB_ZERO_PACKET is easily implemented by increasing td_residue to account for the extra packet. Signed-off-by: David Laight <[email protected]> --- drivers/usb/host/xhci-ring.c | 29 ++++++++++++++++++++++------- 1 file changed, 22 insertions(+), 7 deletions(-) diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c index afd8eeb..1324bb0 100644 --- a/drivers/usb/host/xhci-ring.c +++ b/drivers/usb/host/xhci-ring.c @@ -3296,10 +3296,25 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags, * td_residue is set so that td_residue/max_packet is the number of * packets required to send the data after the current partial * transfer(s) have completed. + * + * If URB_ZERO_PACKET is unset td_residue - urb->transfer_buffer_length + * is always less than or equal to 2 * (max_packet - 1). + * If a ZLP is needed the difference is 2 * max_packet - 1. */ max_packet = GET_MAX_PACKET(usb_endpoint_maxp(&urb->ep->desc)); - td_residue = urb->transfer_buffer_length; - td_residue = ALIGN(td_residue, max_packet) + max_packet - 1; + td_residue = ALIGN(urb->transfer_buffer_length, max_packet); + /* If URB_ZERO_PACKET is set we might need another message. */ + if (urb->transfer_flags & URB_ZERO_PACKET && + td_residue == urb->transfer_buffer_length) { + /* + * For v1.0 hosts we could set the last TRB with td_size == 1, + * but for older hosts we need an extra TRB. + */ + num_trbs++; + /* The td_size in earlier fragments needs to be 1 higher */ + td_residue += max_packet; + } + td_residue += max_packet - 1; ret = prepare_transfer(xhci, xhci->devs[slot_id], ep_index, urb->stream_id, @@ -3343,11 +3358,12 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags, */ trb_buff_len = (~addr & (TRB_MAX_BUFF_SIZE - 1)) + 1; trb_buff_len = min_t(u32, trb_buff_len, this_sg_len); + trb_buff_len = min_t(u32, trb_buff_len, len_left); /* Check for last fragment... */ - if (trb_buff_len >= len_left) { - /* FIXME - add check for ZERO_PACKET flag before this */ - trb_buff_len = len_left; + td_residue -= trb_buff_len; + if (trb_buff_len == len_left && (len_left == 0 || + td_residue < 2 * max_packet - 1)) { urb_priv = urb->hcpriv; urb_priv->td[0]->last_trb = ep_ring->enqueue; /* Request interrupt and clear chain */ @@ -3356,7 +3372,6 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags, } else { if (trb_buff_len == 0) goto next_frag; - td_residue -= trb_buff_len; } /* Set the correct cycle bit (inverted for first TRB). */ @@ -3391,7 +3406,7 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags, /* Advance source data pointer */ this_sg_len -= trb_buff_len; next_frag: - if (this_sg_len == 0) { + if (this_sg_len == 0 && len_left != 0) { sg = sg_next(sg); addr = (u64) sg_dma_address(sg); this_sg_len = sg_dma_len(sg); -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
