kern/37809: new version of dev/ic/gem.c doesn't work on Apple Powerbook5,8

[aymeric%netbsd.org@localhost]

>Number:         37809
>Category:       kern
>Synopsis:       new version of dev/ic/gem.c doesn't work on Apple Powerbook5,8
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sat Jan 19 16:45:00 +0000 2008
>Originator:     Aymeric Vincent
>Release:        -current
>Organization:
>Environment:
NetBSD/macppc
>Description:
rev 1.68 of dev/ic/gem.c introduces a regression which prevents gem from 
correctly working on my powerbook. It still works fine on my iBook.

Apparently, no interrupt is received when a packet arrives on the interface. 
Packets are sent correctly.

>How-To-Repeat:
$ ping -n <some IP>

in another terminal:

$ systat vm 1

see irq of gem0 being triggered only once per second instead of twice when 
dev/ic/gem.c is reverted to 1.67 and works properly.

Also see that the leds on the switch blink at each ping.

# ifconfig gem0 debug

also shows that tx is working properly, but that the irq for reception is never 
taken.

>Fix:
unfortunately, I read the whole diff but it's too big for me to understand in a 
reasonable time.

Reverting to dev/ic/gem.c to 1.67 makes my gem adapter work.