[PATCH] pcnet32: Prevent hang with 79c976

Some boards using the 79c976 pcnet32 chip will hang the system if the
ethtool --register-dump is performed with the device operational.  The
request to read bcr30 is retried by the PCI device infinitely without
returning data, hanging the system.

Tested ia32 and ppc64.

Signed-off-by:  Don Fry <brazilnut@us.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

diff --git a/drivers/net/pcnet32.c b/drivers/net/pcnet32.c
index 549a073..be31922 100644 (file)
--- a/drivers/net/pcnet32.c
+++ b/drivers/net/pcnet32.c
@@ -988,7 +988,11 @@ static void pcnet32_get_regs(struct net_device *dev, struct ethtool_regs *regs,
     *buff++ = a->read_csr(ioaddr, 114);
 
     /* read bus configuration registers */
-    for (i=0; i<36; i++) {
+    for (i=0; i<30; i++) {
+       *buff++ = a->read_bcr(ioaddr, i);
+    }
+    *buff++ = 0;       /* skip bcr30 so as not to hang 79C976 */
+    for (i=31; i<36; i++) {
        *buff++ = a->read_bcr(ioaddr, i);
     }