Hi,
when trying to make the hiddev driver issue several Set_Report control
transfers to a custom device with 2.6.13-rc6, only the first transfer in
a row is carried out, while others immediately following it are silently
dropped.
This happens where hid_submit_report() (in hid-core.c) tests for
HID_CTRL_RUNNING, which seems to be still set because the first transfer
is not finished yet.
As a workaround, inserting a delay between the two calls to
ioctl(HIDIOCSREPORT) in userspace "solves" the problem.
The straightforward fix is to add a call to hid_wait_io() to the
implementation of HIDIOCSREPORT (in hiddev.c), just like for
HIDIOCGREPORT. Works fine for me.
Apparently, this issue has some history:
http://marc.theaimsgroup.com/?l=linux-usb-users&m=111100670105558&w=2
Signed-off-by: Stefan Nickl <[email protected]>
--
Stefan Nickl
Kontron Modular Computers
--- v2.6.13-rc6/drivers/usb/input/hiddev.c.orig 2005-08-22 10:56:55.000000000 +0200
+++ v2.6.13-rc6/drivers/usb/input/hiddev.c 2005-08-22 10:57:07.000000000 +0200
@@ -507,6 +507,7 @@ static int hiddev_ioctl(struct inode *in
return -EINVAL;
hid_submit_report(hid, report, USB_DIR_OUT);
+ hid_wait_io(hid);
return 0;
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