problem with vr0 (enabling polling)

Gary Allan dragonfly at gallan.plus.com
Wed Jan 26 23:29:57 PST 2005


George Georgalis wrote:
On Wed, Jan 26, 2005 at 07:37:02PM +0000, Gary Allan wrote:

I've noticed that polling support for the vr device can not be 
controlled or displayed from ifconfig (Unlike in FreeBSD). Adding the 
following seems to enable that support. No guarantees on correctness but 
maybe someone else can take a look.

cd /usr/src/sys/dev/netif/vr/
diff -ruN if_vr.c if_vr.c.new
--- if_vr.c     2005-01-26 19:19:42.000000000 +0000
+++ if_vr.c.new 2005-01-26 19:26:04.000000000 +0000
@@ -880,6 +880,10 @@
      ifp->if_init = vr_init;
      ifp->if_baudrate = 10000000;
      ifp->if_snd.ifq_maxlen = VR_TX_LIST_CNT - 1;
+#ifdef DEVICE_POLLING
+       ifp->if_capabilities |= IFCAP_POLLING;
+#endif
+       ifp->if_capenable = ifp->if_capabilities;
      /*
       * Do MII setup.
@@ -1690,6 +1694,11 @@
              mii = device_get_softc(sc->vr_miibus);
              error = ifmedia_ioctl(ifp, ifr, &mii->mii_media, command);
              break;
+       case SIOCSIFCAP:
+                ifp->if_capenable &= ~IFCAP_POLLING;
+                ifp->if_capenable |= ifr->ifr_reqcap & IFCAP_POLLING;
+                break;
+
      default:
              error = EINVAL;
              break;
After the modifications with DEVICE_POLLING kernel support and 
kern.polling.enable=1.


Neat, now I can see that polling is really on...

# ifconfig vr0 -polling && ifconfig vr0
vr0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        inet6 fe80::230:1bff:feb4:99a8%vr0 prefixlen 64 scopeid 0x3 
        inet 0.0.0.0 netmask 0xff000000 broadcast 255.255.255.255
        ether 00:30:1b:b4:99:a8
        media: Ethernet none (10baseT/UTP)
        status: no carrier
# ifconfig vr0 polling && ifconfig vr0
vr0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        options=40<polling>
        inet6 fe80::230:1bff:feb4:99a8%vr0 prefixlen 64 scopeid 0x3 
        inet 0.0.0.0 netmask 0xff000000 broadcast 255.255.255.255
        ether 00:30:1b:b4:99:a8
        media: Ethernet none (10baseT/UTP)
        status: no carrier

And I know exactly what people mean by vr0 code stinks, what a mess.

BTW - would it be reasonable to teach patch that tabs and spaces are
both whitespace?
// George

I think this could be a bug.

The vr device has polling support I'm not sure that it can actually be 
enabled. I think this patch (or similar) is needed to set 
ifp->if_capabilities |= IFCAP_POLLING; and set/clear the IFCAP_POLLING 
flag in ifp->if_capenable. As it stands I can't see how 
ifp->if_capenable can ever have this option enabled.

Also the code only tests against ifp.if_flags & IFF_POLLING and again I 
can't see where this flag is set/cleared. Other similar code (rl) tests 
against ifp->if_capenable & IFCAP_POLLING and ifp.if_flags & IFF_POLLING 
but only modifies the if_capenable flags. Can someone explain how 
if_capenable and if_flags operate?

Regards

G.Allan









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