diff options
Diffstat (limited to 'drivers/usb/host/ehci-q.c')
| -rw-r--r-- | drivers/usb/host/ehci-q.c | 48 |
1 files changed, 41 insertions, 7 deletions
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c index 00ad9ce392ed..a427d3b00634 100644 --- a/drivers/usb/host/ehci-q.c +++ b/drivers/usb/host/ehci-q.c @@ -487,8 +487,20 @@ halt: * we must clear the TT buffer (11.17.5). */ if (unlikely(last_status != -EINPROGRESS && - last_status != -EREMOTEIO)) - ehci_clear_tt_buffer(ehci, qh, urb, token); + last_status != -EREMOTEIO)) { + /* The TT's in some hubs malfunction when they + * receive this request following a STALL (they + * stop sending isochronous packets). Since a + * STALL can't leave the TT buffer in a busy + * state (if you believe Figures 11-48 - 11-51 + * in the USB 2.0 spec), we won't clear the TT + * buffer in this case. Strictly speaking this + * is a violation of the spec. + */ + if (last_status != -EPIPE) + ehci_clear_tt_buffer(ehci, qh, urb, + token); + } } /* if we're removing something not at the queue head, @@ -604,9 +616,11 @@ qh_urb_transaction ( ) { struct ehci_qtd *qtd, *qtd_prev; dma_addr_t buf; - int len, maxpacket; + int len, this_sg_len, maxpacket; int is_input; u32 token; + int i; + struct scatterlist *sg; /* * URBs map to sequences of QTDs: one logical transaction @@ -647,7 +661,20 @@ qh_urb_transaction ( /* * data transfer stage: buffer setup */ - buf = urb->transfer_dma; + i = urb->num_sgs; + if (len > 0 && i > 0) { + sg = urb->sg->sg; + buf = sg_dma_address(sg); + + /* urb->transfer_buffer_length may be smaller than the + * size of the scatterlist (or vice versa) + */ + this_sg_len = min_t(int, sg_dma_len(sg), len); + } else { + sg = NULL; + buf = urb->transfer_dma; + this_sg_len = len; + } if (is_input) token |= (1 /* "in" */ << 8); @@ -663,7 +690,9 @@ qh_urb_transaction ( for (;;) { int this_qtd_len; - this_qtd_len = qtd_fill(ehci, qtd, buf, len, token, maxpacket); + this_qtd_len = qtd_fill(ehci, qtd, buf, this_sg_len, token, + maxpacket); + this_sg_len -= this_qtd_len; len -= this_qtd_len; buf += this_qtd_len; @@ -679,8 +708,13 @@ qh_urb_transaction ( if ((maxpacket & (this_qtd_len + (maxpacket - 1))) == 0) token ^= QTD_TOGGLE; - if (likely (len <= 0)) - break; + if (likely(this_sg_len <= 0)) { + if (--i <= 0 || len <= 0) + break; + sg = sg_next(sg); + buf = sg_dma_address(sg); + this_sg_len = min_t(int, sg_dma_len(sg), len); + } qtd_prev = qtd; qtd = ehci_qtd_alloc (ehci, flags); |