kern/161277: [patch][if_em] BMC cannot receive IPMI traffic after loading or enabling the if_em driver

[Rafael NAVAZA]

>Number:         161277
>Category:       kern
>Synopsis:       [patch][if_em] BMC cannot receive IPMI traffic after loading or enabling the if_em driver
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Oct 04 11:30:16 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator:     Rafael NAVAZA
>Release:        FreeBSD 8.2
>Organization:
Institut Pasteur
>Environment:
FreeBSD frbox 8.2-RELEASE FreeBSD 8.2-RELEASE #0: Fri Feb 18 02:24:46 UTC 2011     root at almeida.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC  i386
>Description:
With Intel 82473E NICs, the BMC cannot receive IPMI-over-LAN traffic after loading or enabling the if_em driver.
>How-To-Repeat:
Get a machine with BMC enabled Intel 82573E NIC, and try to "ifconfig" the "em" interfaces.
Then the BMC will stop responding to the IPMI-over-LAN traffic.
>Fix:
Disable the CRC stripping in the if_em driver.

Proposed fix : Add an "em.disable_crc_stripping" option to the if_em driver. 


Patch attached with submission follows:

--- /usr/src/sys/dev/e1000/if_em.c	2011-01-26 00:20:22.000000000 +0100
+++ /usr/src/sys/dev/e1000/if_em.c.disable_crc_stripping	2011-09-15 12:44:23.000000000 +0200
@@ -332,6 +332,12 @@
 #define CSUM_TSO	0
 #endif
 
+static int em_disable_crc_stripping = 0;
+TUNABLE_INT("hw.em.disable_crc_stripping", &em_disable_crc_stripping);
+
+SYSCTL_NODE(_hw, OID_AUTO, em, CTLFLAG_RD, 0, "EM driver parameters");
+SYSCTL_INT(_hw_em, OID_AUTO, disable_crc_stripping, CTLFLAG_RD, &em_disable_crc_stripping, 0, "Disable CRC Stripping");
+
 static int em_tx_int_delay_dflt = EM_TICKS_TO_USECS(EM_TIDV);
 static int em_rx_int_delay_dflt = EM_TICKS_TO_USECS(EM_RDTR);
 TUNABLE_INT("hw.em.tx_int_delay", &em_tx_int_delay_dflt);
@@ -4150,7 +4156,8 @@
 	    (hw->mac.mc_filter_type << E1000_RCTL_MO_SHIFT);
 
         /* Strip the CRC */
-        rctl |= E1000_RCTL_SECRC;
+        if (!em_disable_crc_stripping)
+		rctl |= E1000_RCTL_SECRC;
 
         /* Make sure VLAN Filters are off */
         rctl &= ~E1000_RCTL_VFE;


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