kern/128766: [ PATCH ] VGE's [rt]xcsum can't be switched off

[Dan Lukes]

>Number:         128766
>Category:       kern
>Synopsis:       [ PATCH ] VGE's [rt]xcsum can't be switched off
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Nov 10 21:30:01 UTC 2008
>Closed-Date:
>Last-Modified:
>Originator:     Dan Lukes
>Release:        FreeBSD
>Organization:
Obludarium
>Environment:
FreeBSD >=6.0, >=7.0, CURRENT

if_vge.c revisions
HEAD:     >=1.19 (affect all 7.x releases also)
RELENG_6: >=1.14.2.3 (e.g. 6.0-RELEASE and newer)


>Description:
	During the Glebius's "big polling(4) cleanup"
of the VGE network card driver the processing of 
(re)set of {r|t}xcsum capabilities has been broken.

The line
ifp->if_capenable &= -IFCAP_HWCSUM; 
disapeared from code and the current code ...
 -----------
if (mask & IFCAP_HWCSUM) {
   ifp->if_capenable |= ifr->ifr_reqcap & (IFCAP_HWCSUM);
 -----------

... allow no deactivation of capabilities. 
As both of *csum are activated on default, there 
is no way to turn them off.

>How-To-Repeat:
	Try ifconfig vge0 -txcsum -rxcsum - it do nothing

>Fix:

I hope it will be MFCed not only to RELENG_7 but into RELENG_6
as well (I not trying to ask it will be MFCed into RELENG_6_4 also)


--- /usr/src/sys/dev/vge/if_vge.c.orig	2008-11-10 16:50:21.000000000 +0100
+++ /usr/src/sys/dev/vge/if_vge.c	2008-11-10 21:01:08.000000000 +0100
@@ -2230,7 +2230,7 @@
 		}
 #endif /* DEVICE_POLLING */
 		if (mask & IFCAP_HWCSUM) {
-			ifp->if_capenable |= ifr->ifr_reqcap & (IFCAP_HWCSUM);
+			ifp->if_capenable ^= (mask & IFCAP_HWCSUM);
 			if (ifp->if_capenable & IFCAP_TXCSUM)
 				ifp->if_hwassist = VGE_CSUM_FEATURES;
 			else
>Release-Note:
>Audit-Trail:
>Unformatted: