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| author | Alan Stern <stern@rowland.harvard.edu> | 2017-11-08 18:23:17 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-11-09 13:02:23 +0100 |
| commit | 2ef47001b3ee3ded579b7532ebdcf8680e4d8c54 (patch) | |
| tree | f18359ee963f40e6fbdf3ecac25d55c79baad293 /drivers | |
| parent | usb: core: message: remember to reset 'ret' to 0 when necessary (diff) | |
| download | linux-2ef47001b3ee3ded579b7532ebdcf8680e4d8c54.tar.xz linux-2ef47001b3ee3ded579b7532ebdcf8680e4d8c54.zip | |
USB: usbfs: compute urb->actual_length for isochronous
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>
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
| -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 c3aaafc25a04..2edb4e7b2ab8 100644 --- a/drivers/usb/core/devio.c +++ b/drivers/usb/core/devio.c @@ -1820,6 +1820,18 @@ 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; @@ -1827,6 +1839,7 @@ 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; @@ -1995,6 +2008,7 @@ 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; |