From stern@rowland.harvard.edu Mon Jan 8 09:01:52 2007 From: Alan Stern Date: Mon, 8 Jan 2007 12:01:43 -0500 (EST) Subject: UHCI: no dummy TDs for Iso QHs To: Greg KH Message-ID: Isochronous queues don't need a dummy TD because the Queue Header isn't managed by the hardware. This patch (as836) removes the unnecessary dummy TDs. The patch also fixes a long-standing typo in a comment (a "don't" was missing -- potentially very confusing!). Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/uhci-debug.c | 2 +- drivers/usb/host/uhci-q.c | 17 ++++++++++------- 2 files changed, 11 insertions(+), 8 deletions(-) --- gregkh-2.6.orig/drivers/usb/host/uhci-debug.c +++ gregkh-2.6/drivers/usb/host/uhci-debug.c @@ -208,7 +208,7 @@ static int uhci_show_qh(struct uhci_qh * space, "", nurbs); } - if (qh->udev) { + if (qh->dummy_td) { out += sprintf(out, "%*s Dummy TD\n", space, ""); out += uhci_show_td(qh->dummy_td, out, len - (out - buf), 0); } --- gregkh-2.6.orig/drivers/usb/host/uhci-q.c +++ gregkh-2.6/drivers/usb/host/uhci-q.c @@ -248,16 +248,18 @@ static struct uhci_qh *uhci_alloc_qh(str INIT_LIST_HEAD(&qh->node); if (udev) { /* Normal QH */ - qh->dummy_td = uhci_alloc_td(uhci); - if (!qh->dummy_td) { - dma_pool_free(uhci->qh_pool, qh, dma_handle); - return NULL; + qh->type = hep->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK; + if (qh->type != USB_ENDPOINT_XFER_ISOC) { + qh->dummy_td = uhci_alloc_td(uhci); + if (!qh->dummy_td) { + dma_pool_free(uhci->qh_pool, qh, dma_handle); + return NULL; + } } qh->state = QH_STATE_IDLE; qh->hep = hep; qh->udev = udev; hep->hcpriv = qh; - qh->type = hep->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK; } else { /* Skeleton QH */ qh->state = QH_STATE_ACTIVE; @@ -275,7 +277,8 @@ static void uhci_free_qh(struct uhci_hcd list_del(&qh->node); if (qh->udev) { qh->hep->hcpriv = NULL; - uhci_free_td(uhci, qh->dummy_td); + if (qh->dummy_td) + uhci_free_td(uhci, qh->dummy_td); } dma_pool_free(uhci->qh_pool, qh, qh->dma_handle); } @@ -327,7 +330,7 @@ static int uhci_cleanup_queue(struct uhc goto done; qh->element = UHCI_PTR_TERM; - /* Control pipes have to worry about toggles */ + /* Control pipes don't have to worry about toggles */ if (qh->type == USB_ENDPOINT_XFER_CONTROL) goto done;