diff options
| -rw-r--r-- | drivers/usb/host/ehci-hcd.c | 36 |
1 files changed, 19 insertions, 17 deletions
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index 55f4436..0ffd6f1 100644 --- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -1154,6 +1154,23 @@ create_int_queue(struct usb_device *dev, unsigned long pipe, int queuesize, struct int_queue *result = NULL; int i; + /* + * Interrupt transfers requiring several transactions are not supported + * because bInterval is ignored. + * + * Also, ehci_submit_async() relies on wMaxPacketSize being a power of 2 + * <= PKT_ALIGN if several qTDs are required, while the USB + * specification does not constrain this for interrupt transfers. That + * means that ehci_submit_async() would support interrupt transfers + * requiring several transactions only as long as the transfer size does + * not require more than a single qTD. + */ + if (elementsize > usb_maxpacket(dev, pipe)) { + printf("%s: xfers requiring several transactions are not supported.\n", + __func__); + return NULL; + } + debug("Enter create_int_queue\n"); if (usb_pipetype(pipe) != PIPE_INTERRUPT) { debug("non-interrupt pipe (type=%lu)", usb_pipetype(pipe)); @@ -1375,24 +1392,9 @@ submit_int_msg(struct usb_device *dev, unsigned long pipe, void *buffer, debug("dev=%p, pipe=%lu, buffer=%p, length=%d, interval=%d", dev, pipe, buffer, length, interval); - /* - * Interrupt transfers requiring several transactions are not supported - * because bInterval is ignored. - * - * Also, ehci_submit_async() relies on wMaxPacketSize being a power of 2 - * <= PKT_ALIGN if several qTDs are required, while the USB - * specification does not constrain this for interrupt transfers. That - * means that ehci_submit_async() would support interrupt transfers - * requiring several transactions only as long as the transfer size does - * not require more than a single qTD. - */ - if (length > usb_maxpacket(dev, pipe)) { - printf("%s: Interrupt transfers requiring several " - "transactions are not supported.\n", __func__); - return -1; - } - queue = create_int_queue(dev, pipe, 1, length, buffer); + if (!queue) + return -1; timeout = get_timer(0) + USB_TIMEOUT_MS(pipe); while ((backbuffer = poll_int_queue(dev, queue)) == NULL) |