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author | Alan Stern <stern@rowland.harvard.edu> | 2017-11-08 20:23:17 +0300 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-11-09 15:02:23 +0300 |
commit | 2ef47001b3ee3ded579b7532ebdcf8680e4d8c54 (patch) | |
tree | f18359ee963f40e6fbdf3ecac25d55c79baad293 /drivers/usb/misc/sisusbvga/sisusb.c | |
parent | d656fa32b13424701bb85f6b5183ea869b363799 (diff) | |
download | linux-2ef47001b3ee3ded579b7532ebdcf8680e4d8c54.tar.xz |
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/usb/misc/sisusbvga/sisusb.c')
0 files changed, 0 insertions, 0 deletions