usb/94311: [ugen][PATCH] allow interrupt IN transactions to be affected by USB_SET_TIMEOUT

[Lonnie Mendez]

>Number:         94311
>Category:       usb
>Synopsis:       [ugen][PATCH] allow interrupt IN transactions to be affected by USB_SET_TIMEOUT
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-usb
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sat Mar 11 05:50:20 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator:     Lonnie Mendez
>Release:        6.1-BETA2
>Organization:
>Environment:
FreeBSD twind 6.1-BETA2 FreeBSD 6.1-BETA2 #4: Fri Mar 10 22:09:38 CST 2006     root at twind:/usr/src/sys/i386/compile/MYKERNEL  i386
>Description:
   While developing the usb redirector for qemu on FreeBSD I ran into the fact that the interrupt transaction process in ugen.c:ugen_do_read() does not allow for a timeout value (hangs process without O_NONBLOCK and no data).  The man page for ugen also does not mention that USB_SET_TIMEOUT ioctl has no effect for interrupt IN transaction so I'm led to believe this is a bug/feature not yet fixed:

     USB_SET_TIMEOUT (int)
	     Set the timeout on the device operations, the time is specified
	     in milliseconds.  The value 0 is used to indicate that there is
	     no timeout.

   The patch below I believe corrects for this by using the timeout value that can be set from USB_SET_TIMEOUT ioctl in the tsleep call.  With this patch the redirector can maintain the KISS principle while functioning properly.
>How-To-Repeat:

>Fix:
--- sys/dev/usb/ugen.c	Fri Mar 10 23:17:56 2006
+++ sys/dev/usb/ugen.c	Fri Mar 10 22:28:32 2006
@@ -726,12 +726,15 @@
 			}
 			sce->state |= UGEN_ASLP;
 			DPRINTFN(5, ("ugenread: sleep on %p\n", sce));
-			error = tsleep(sce, PZERO | PCATCH, "ugenri", 0);
+			error = tsleep(sce, PZERO | PCATCH, "ugenri",
+					(sce->timeout*hz+999)/1000);
 			DPRINTFN(5, ("ugenread: woke, error=%d\n", error));
 			if (sc->sc_dying)
 				error = EIO;
 			if (error) {
 				sce->state &= ~UGEN_ASLP;
+				if (error == EWOULDBLOCK)
+					error = ETIMEDOUT;
 				break;
 			}
 		}

>Release-Note:
>Audit-Trail:
>Unformatted: