kern/43753: write-timeout in ugen(4) cannot be set

[Wolfgang.Stukenbrock%nagler-company.com@localhost]

>Number:         43753
>Category:       kern
>Synopsis:       write-timeout in ugen(4) cannot be set
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Fri Aug 13 12:00:00 +0000 2010
>Originator:     Wolfgang Stukenbrock
>Release:        NetBSD 5.0.2
>Organization:
Dr. Nagler & Company GmbH
        
>Environment:
        
        
System: NetBSD test-s0 4.0 NetBSD 4.0 (NSW-WS) #1: Fri Aug 13 13:24:12 CEST 
2010 wgstuken@test-s0:/usr/src/sys/arch/amd64/compile/NSW-WS amd64
Architecture: x86_64
Machine: amd64
>Description:
        In the current implementation it is impossible to set a timeout on 
write operations
        in the ugen(4) driver.
        The USB_SET_TIMEOUT sets the timeout value only for the IN pipe. The 
OUT pipe is not
        modified. There seems to be no way to set a value other than the 
default assigned
        durint openening the endpoint to the OUT pipe. I've check the most 
reachend file
        in the CVS repository - so this problem is in current too.

        The manual to ugen(4) say: USB_SET_TIMEOUT will set the timeout on the 
device operations.
        This meens both IN and OUT - at least this is my understanding.
        If only setting of the IN-timeout is desired, this should be clarified 
in the manual.

        There are at least two ways to fix this problem:
        1: set the OUT-timeout to the same value as for the IN pipe in the 
USB_SET_TIMEOUT.
        2. add another ioctl to set the OUT-timeout seperately.
           Perhaps the USB_SET_TIMEOUT should set both timeouts and two new 
ioctls (e.g.
           USB_SET_IN_TIMEOUT and USB_SET_OUT_TIMEOUT) should be created to 
support
           different timeout settings for read(2) and write(2) operations.

        The fix below just does version 1, but I think the second one would be 
the most flexible.
>How-To-Repeat:
        Try to set a timeout and send more data as the device is actual able to 
accept.
        The write() call will hang forever ...
>Fix:
        The following patch will set the timeout for the OUT pipe to the same 
value as the
        IN pipe on USB_SET_TIMEOUT ioctl.
        remark: This fix will return EINVAL if the IN-pipe is invalid, even if 
an OUT-pipe
                is present. As far as I've seen in the code, this situation 
will never happen.

--- ugen.c.orig 2010-08-13 13:38:39.000000000 +0200
+++ ugen.c      2010-08-13 13:38:17.000000000 +0200
@@ -1427,6 +1427,8 @@
                        )
                        return (EINVAL);
                sce->timeout = *(int *)addr;
+               if ((sce = &sc->sc_endpoints[endpt][OUT]) != NULL)
+                       sce->timeout = *(int *)addr;
                return (0);
        case USB_SET_BULK_RA:
 #ifdef UGEN_BULK_RA_WB

>Unformatted: