2.6.7-mm1 PCNet Problems under VMWare 4.5.2

[Keith Moore <keithmo@exmsft.com>]

I'm seeing problems running a 2.6.7-mm1 kernel with Fedora Core 2 
running in a VMWare Workstation 4.5.2 VM. The kernel hangs trying to 
bring up the (dhcp-enabled) eth0 interface.

I dug through the -mm1 patch, and the problem seems to be the changes at 
the end of the pcnet32_interrupt() function (in drivers/net/pcnet32.c). 
The relevant patch fragment is:

-    /* Clear any other interrupt, and set interrupt enable. */
-    lp->a.write_csr (ioaddr, 0, 0x7940);
+    /* Set interrupt enable. */
+    lp->a.write_csr (ioaddr, 0, 0x0040);

Reverting this one section of the patch makes eth0 happy again.

I poked around with the values written to the csr register, and it 
appears the virtual PCNet-II adapter needs bit 0x0100 (initialzation 
done) set. So, writing 0x0140 instead of 0x0040 seems to work well.

I have no idea how accurate VMWare's emulation of this adapter is, or if 
this change may cause problems with other (physical) adapters.


KM