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authorAlan Stern <stern@rowland.harvard.edu>2017-11-08 12:23:17 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-11-21 09:01:07 +0100
commit6a5d144279755576826148b94b28f652bdf0cca3 (patch)
treea09f1149302a211d415151a9b6528d77ad7d7d65
parent8cf8ebdce459c57c9ca75448e29feced04dcfd79 (diff)
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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.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index d7edec160a6d..f322111db601 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -1649,6 +1649,18 @@ 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;
@@ -1656,6 +1668,7 @@ 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;
@@ -1825,6 +1838,7 @@ 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;