[src/trunk]: src/sys/net ifmedia_set() should not panic, nor can it really fa...

[briggs <briggs%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/aa84be5f737c
branches:  trunk
changeset: 554871:aa84be5f737c
user:      briggs <briggs%NetBSD.org@localhost>
date:      Mon Nov 03 14:43:32 2003 +0000

description:
ifmedia_set() should not panic, nor can it really fail.  So if there is
some problem setting the media to the requested value (usually IFM_AUTO),
we now force the media selection to IFM_NONE.
This addresses PR/14029 ``panic("ifmedia_set") a little too brutal''
and may address to some degree PR/19504 and PR/23341.

diffstat:

 sys/net/if_media.c |  29 +++++++++++++++++++++++++----
 1 files changed, 25 insertions(+), 4 deletions(-)

diffs (58 lines):

diff -r 3e2f84862e25 -r aa84be5f737c sys/net/if_media.c
--- a/sys/net/if_media.c        Mon Nov 03 12:22:17 2003 +0000
+++ b/sys/net/if_media.c        Mon Nov 03 14:43:32 2003 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: if_media.c,v 1.19 2003/07/25 19:35:57 christos Exp $   */
+/*     $NetBSD: if_media.c,v 1.20 2003/11/03 14:43:32 briggs Exp $     */
 
 /*-
  * Copyright (c) 1998 The NetBSD Foundation, Inc.
@@ -83,7 +83,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_media.c,v 1.19 2003/07/25 19:35:57 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_media.c,v 1.20 2003/11/03 14:43:32 briggs Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -190,16 +190,37 @@
 ifmedia_set(ifm, target)
        struct ifmedia *ifm; 
        int target;
-
 {
        struct ifmedia_entry *match;
 
        match = ifmedia_match(ifm, target, ifm->ifm_mask);
 
+       /*
+        * If we didn't find the requested media, then we try to fall
+        * back to target-type (IFM_ETHER, e.g.) | IFM_NONE.  If that's
+        * not on the list, then we add it and set the media to it.
+        *
+        * Since ifmedia_set is almost always called with IFM_AUTO or
+        * with a known-good media, this really should only occur if we:
+        *
+        * a) didn't find any PHYs, or
+        * b) didn't find an autoselect option on the PHY when the
+        *    parent ethernet driver expected to.
+        *
+        * In either case, it makes sense to select no media.
+        */
        if (match == NULL) {
                printf("ifmedia_set: no match for 0x%x/0x%x\n",
                    target, ~ifm->ifm_mask);
-               panic("ifmedia_set");
+               target = (target & IFM_NMASK) | IFM_NONE;
+               match = ifmedia_match(ifm, target, ifm->ifm_mask);
+               if (match == NULL) {
+                       ifmedia_add(ifm, target, 0, NULL);
+                       match = ifmedia_match(ifm, target, ifm->ifm_mask);
+                       if (match == NULL) {
+                               panic("ifmedia_set failed");
+                       }
+               }
        }
        ifm->ifm_cur = match;