3.2.99-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Alan Stern <[email protected]> commit 2ef47001b3ee3ded579b7532ebdcf8680e4d8c54 upstream. The USB kerneldoc says that the actual_length field "is read in non-iso completion functions", but the usbfs driver uses it for all URB types in processcompl(). Since not all of the host controller drivers set actual_length for isochronous URBs, programs using usbfs with some host controllers don't work properly. For example, Minas reports that a USB camera controlled by libusb doesn't work properly with a dwc2 controller. It doesn't seem worthwhile to change the HCDs and the documentation, since the in-kernel USB class drivers evidently don't rely on actual_length for isochronous transfers. The easiest solution is for usbfs to calculate the actual_length value for itself, by adding up the lengths of the individual packets in an isochronous transfer. Signed-off-by: Alan Stern <[email protected]> CC: Minas Harutyunyan <[email protected]> Reported-and-tested-by: wlf <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> Signed-off-by: Ben Hutchings <[email protected]> --- drivers/usb/core/devio.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -1402,6 +1402,18 @@ static int proc_unlinkurb(struct dev_sta return 0; } +static void compute_isochronous_actual_length(struct urb *urb) +{ + unsigned int i; + + if (urb->number_of_packets > 0) { + urb->actual_length = 0; + for (i = 0; i < urb->number_of_packets; i++) + urb->actual_length += + urb->iso_frame_desc[i].actual_length; + } +} + static int processcompl(struct async *as, void __user * __user *arg) { struct urb *urb = as->urb; @@ -1409,6 +1421,7 @@ static int processcompl(struct async *as void __user *addr = as->userurb; unsigned int i; + compute_isochronous_actual_length(urb); if (as->userbuffer && urb->actual_length) { if (urb->number_of_packets > 0) /* Isochronous */ i = urb->transfer_buffer_length; @@ -1581,6 +1594,7 @@ static int processcompl_compat(struct as void __user *addr = as->userurb; unsigned int i; + compute_isochronous_actual_length(urb); if (as->userbuffer && urb->actual_length) { if (urb->number_of_packets > 0) /* Isochronous */ i = urb->transfer_buffer_length;
