From 3a99da700874289ab4b000840cd8e0e0cbe8646e Mon Sep 17 00:00:00 2001 From: Nikias Bassen Date: Sat, 29 Aug 2009 16:40:31 +0200 Subject: [PATCH] Linux: Correctly terminate bulk packets of size wMaxPacketSize ... and multiples. This patch will automatically set the URB_ZERO_PACKET flag if the packet size is a multiple of the endpoint's wMaxPacketSize so that the kernel actually submits bulk packet. This is only for outgoing transfers. --- libusb/os/linux_usbfs.c | 18 ++++++++++++++++++ libusb/os/linux_usbfs.h | 1 + 2 files changed, 19 insertions(+), 0 deletions(-) diff --git a/libusb/os/linux_usbfs.c b/libusb/os/linux_usbfs.c index 1280188..ad1dc89 100644 --- a/libusb/os/linux_usbfs.c +++ b/libusb/os/linux_usbfs.c @@ -1265,6 +1265,8 @@ static int submit_bulk_transfer(struct usbi_transfer *itransfer, int r; int i; size_t alloc_size; + uint8_t is_read; /* 0 = we're reading, 1 = we're writing */ + uint8_t flag_zero_packet = 0; /* 0 = don't flag, 1 = flag */ if (tpriv->urbs) return LIBUSB_ERROR_BUSY; @@ -1294,6 +1296,17 @@ static int submit_bulk_transfer(struct usbi_transfer *itransfer, tpriv->num_retired = 0; tpriv->reap_action = NORMAL; + /* are we reading or writing? */ + is_read = transfer->endpoint & LIBUSB_ENDPOINT_IN; + if (!is_read) { + libusb_device *tdev = libusb_get_device(transfer->dev_handle); + int max_packet_size = libusb_get_max_packet_size(tdev, transfer->endpoint); + if ((max_packet_size > 0) && (transfer->length > 0) + && (transfer->length % max_packet_size == 0)) { + flag_zero_packet = 1; + } + } + for (i = 0; i < num_urbs; i++) { struct usbfs_urb *urb = &urbs[i]; urb->usercontext = itransfer; @@ -1307,6 +1320,11 @@ static int submit_bulk_transfer(struct usbi_transfer *itransfer, else urb->buffer_length = MAX_BULK_BUFFER_LENGTH; + if ((i == num_urbs - 1) && (flag_zero_packet)) { + printf("flagging URB_ZERO_PACKET\n"); + urb->flags |= USBFS_URB_ZERO_PACKET; + } + r = ioctl(dpriv->fd, IOCTL_USBFS_SUBMITURB, urb); if (r < 0) { int j; diff --git a/libusb/os/linux_usbfs.h b/libusb/os/linux_usbfs.h index fdf5e9b..9ed0b4f 100644 --- a/libusb/os/linux_usbfs.h +++ b/libusb/os/linux_usbfs.h @@ -63,6 +63,7 @@ struct usbfs_getdriver { #define USBFS_URB_DISABLE_SPD 1 #define USBFS_URB_ISO_ASAP 2 #define USBFS_URB_QUEUE_BULK 0x10 +#define USBFS_URB_ZERO_PACKET 0x40 enum usbfs_urb_type { USBFS_URB_TYPE_ISO = 0, -- 1.6.0.4