diff options
Diffstat (limited to 'libusb/core.c')
| -rw-r--r-- | libusb/core.c | 30 |
1 files changed, 23 insertions, 7 deletions
diff --git a/libusb/core.c b/libusb/core.c index ddba089..6206b85 100644 --- a/libusb/core.c +++ b/libusb/core.c @@ -1079,7 +1079,9 @@ out: * If acting on an isochronous or interrupt endpoint, this function will * multiply the value found in bits 0:10 by the number of transactions per * microframe (determined by bits 11:12). Otherwise, this function just - * returns the numeric value found in bits 0:10. + * returns the numeric value found in bits 0:10. For USB 3.0 device, it + * will attempts to retrieve the Endpoint Companion Descriptor to return + * wBytesPerInterval. * * This function is useful for setting up isochronous transfers, for example * you might pass the return value from this function to @@ -1099,9 +1101,11 @@ int API_EXPORTED libusb_get_max_iso_packet_size(libusb_device *dev, { struct libusb_config_descriptor *config; const struct libusb_endpoint_descriptor *ep; + struct libusb_ss_endpoint_companion_descriptor *ss_ep_cmp; enum libusb_transfer_type ep_type; uint16_t val; int r; + int speed; r = libusb_get_active_config_descriptor(dev, &config); if (r < 0) { @@ -1116,13 +1120,25 @@ int API_EXPORTED libusb_get_max_iso_packet_size(libusb_device *dev, goto out; } - val = ep->wMaxPacketSize; - ep_type = (enum libusb_transfer_type) (ep->bmAttributes & 0x3); + speed = libusb_get_device_speed( dev ); + if (speed == LIBUSB_SPEED_SUPER) { + r = libusb_get_ss_endpoint_companion_descriptor(dev->ctx, ep, &ss_ep_cmp); + if (r == LIBUSB_SUCCESS) { + r = ss_ep_cmp->wBytesPerInterval; + libusb_free_ss_endpoint_companion_descriptor(ss_ep_cmp); + } + } - r = val & 0x07ff; - if (ep_type == LIBUSB_TRANSFER_TYPE_ISOCHRONOUS - || ep_type == LIBUSB_TRANSFER_TYPE_INTERRUPT) - r *= (1 + ((val >> 11) & 3)); + /* If the device isn't a SuperSpeed device or retrieving the SS endpoint didn't worked. */ + if (speed != LIBUSB_SPEED_SUPER || r < 0) { + val = ep->wMaxPacketSize; + ep_type = (enum libusb_transfer_type) (ep->bmAttributes & 0x3); + + r = val & 0x07ff; + if (ep_type == LIBUSB_TRANSFER_TYPE_ISOCHRONOUS + || ep_type == LIBUSB_TRANSFER_TYPE_INTERRUPT) + r *= (1 + ((val >> 11) & 3)); + } out: libusb_free_config_descriptor(config); |