diff options
| author | Alan Stern <stern@rowland.harvard.edu> | 2017-11-08 12:23:17 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-11-21 09:21:23 +0100 |
| commit | 965003b311e0ed764eb6c0d6f86fe14a57d43286 (patch) | |
| tree | f1e6c7596ab57998822e71111237b3eb6d743ee7 | |
| parent | 834a5d880a54008e62ba501785337b7f51c43b39 (diff) | |
USB: usbfs: compute urb->actual_length for isochronous
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 <stern@rowland.harvard.edu>
CC: Minas Harutyunyan <Minas.Harutyunyan@synopsys.com>
Reported-and-tested-by: wlf <wulf@rock-chips.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/usb/core/devio.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c index 873ba02d59e6..f4c3a37e00ba 100644 --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -1653,6 +1653,18 @@ static int proc_unlinkurb(struct usb_dev_state *ps, void __user *arg) 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; @@ -1660,6 +1672,7 @@ static int processcompl(struct async *as, void __user * __user *arg) void __user *addr = as->userurb; unsigned int i; + compute_isochronous_actual_length(urb); if (as->userbuffer && urb->actual_length) { if (copy_urb_data_to_user(as->userbuffer, urb)) goto err_out; @@ -1829,6 +1842,7 @@ static int processcompl_compat(struct async *as, void __user * __user *arg) void __user *addr = as->userurb; unsigned int i; + compute_isochronous_actual_length(urb); if (as->userbuffer && urb->actual_length) { if (copy_urb_data_to_user(as->userbuffer, urb)) return -EFAULT; |