svn commit: r286829 - in head: share/man/man4 sys/dev/e1000

[Sean Bruno]

Author: sbruno
Date: Sun Aug 16 19:06:23 2015
New Revision: 286829
URL: https://svnweb.freebsd.org/changeset/base/286829

Log:
  Add capability to disable CRC stripping. This breaks IPMI/BMC capabilities on certain adatpers.
  Linux has been doing the exact same thing since 2008
  
  https://github.com/torvalds/linux/commit/eb7c3adb1ca92450870dbb0d347fc986cd5e2af4
  
  PR:	161277
  Differential Revision:	https://reviews.freebsd.org/D3282
  Submitted by:	Fravadona at gmail.com
  Reviewed by:	erj wblock
  MFC after:	2 weeks
  Relnotes:	yes
  Sponsored by:	Limelight Networks

Modified:
  head/share/man/man4/em.4
  head/sys/dev/e1000/if_em.c

Modified: head/share/man/man4/em.4
==============================================================================
--- head/share/man/man4/em.4	Sun Aug 16 17:07:53 2015	(r286828)
+++ head/share/man/man4/em.4	Sun Aug 16 19:06:23 2015	(r286829)
@@ -31,7 +31,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd October 11, 2011
+.Dd August 16, 2015
 .Dt EM 4
 .Os
 .Sh NAME
@@ -205,6 +205,11 @@ Tunables can be set at the
 prompt before booting the kernel or stored in
 .Xr loader.conf 5 .
 .Bl -tag -width indent
+.It Va hw.em.disable_crc_stripping
+Disable or enable hardware stripping of CRC field.
+This is mostly useful on BMC/IPMI shared interfaces where stripping the CRC
+causes remote access over IPMI to fail.
+Default 0 (enabled).
 .It Va hw.em.eee_setting
 Disable or enable Energy Efficient Ethernet.
 Default 1 (disabled).

Modified: head/sys/dev/e1000/if_em.c
==============================================================================
--- head/sys/dev/e1000/if_em.c	Sun Aug 16 17:07:53 2015	(r286828)
+++ head/sys/dev/e1000/if_em.c	Sun Aug 16 19:06:23 2015	(r286829)
@@ -366,6 +366,10 @@ MODULE_DEPEND(em, netmap, 1, 1, 1);
 
 static SYSCTL_NODE(_hw, OID_AUTO, em, CTLFLAG_RD, 0, "EM driver parameters");
 
+static int em_disable_crc_stripping = 0;
+SYSCTL_INT(_hw_em, OID_AUTO, disable_crc_stripping, CTLFLAG_RDTUN,
+    &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);
 SYSCTL_INT(_hw_em, OID_AUTO, tx_int_delay, CTLFLAG_RDTUN, &em_tx_int_delay_dflt,
@@ -4514,7 +4518,8 @@ em_initialize_receive_unit(struct adapte
 	    (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;