Bug 18768

	I can't get the "dc" driver to work properly with a Digital DE500-BA
	card on an Alpha.  I am running -current from April 9 (revision 1.9 of
	if_dc.c).  This same card with the same cable and switch works fine
	when I boot Tru64 Unix (aka Digital Unix 5.0).  Here are the symptoms
	when I use FreeBSD's "dc" driver:

	With ifconfig media set to autoselect:

	    - boot system: lights on the switch say it's 100 Mbit half-duplex.
	      (The switch is an Allied Telesyn (CentreCom) FS716.)

	    - ifconfig says it's full-duplex

	    - unplug cable from switch and replug it: switch lights now say
	      full-duplex

	    - send a big file via ftp: system prints TX underrun warning,
	      switch lights go off and come back up half-duplex.

	    - unplug cable from switch and replug it: switch lights now say
	      full-duplex

	    - send a big file again: everything is OK now

	With ifconfig media set to 100baseTX full-duplex:

	    - boot system: lights on the switch say it's 100 Mbit half-duplex

	    - ifconfig says it's full-duplex

	    - replugging cable doesn't change anything

	With ifconfig media set to 10baseTX/UTP:

	    - works fine, but hey, it's only 10 Mbit

	I tried backing up to revision 1.8 of if_dc.c to remove this commit:

	    msmith      2000/03/10 21:20:58 PST

	      Modified files:
		sys/pci              if_dc.c if_dcreg.h 
	      Log:
	      Teach the 'dc' driver how to pick up settings left over by the
	      SRM on alpha systems.  This is an expedient if not entirely
	      elegant solution to the problem.

	It didn't help.

	Dmesg output is below.  (The kernel was built May 20, but the
	sources are actually from April 9.)

	Copyright (c) 1992-2000 The FreeBSD Project.
	Copyright (c) 1982, 1986, 1989, 1991, 1993
		The Regents of the University of California. All rights reserved.
	FreeBSD 5.0-CURRENT #3: Sat May 20 12:22:22 PDT 2000
	    jdp@alpha.polstra.com:/c/src/sys/compile/ALPHA
	EB164
	Digital AlphaPC 164LX 533 MHz, 531MHz
	8192 byte page size, 1 processor.
	CPU: EV56 (21164A) major=7 minor=2 extensions=0x1<BWX>
	OSF PAL rev: 0x1000200020117
	real memory  = 132046848 (128952K bytes)
	avail memory = 124321792 (121408K bytes)
	Preloaded elf kernel "kernel" at 0xfffffc0000602000.
	cia0: Pyxis, pass 1
	cia0: extended capabilities: 1<BWEN>
	pcib0: <2117x PCI host bus adapter> on cia0
	pci0: <PCI bus> on pcib0
	dc0: <Intel 21143 10/100BaseTX> port 0x1100-0x117f mem 0x82271100-0x8227117f irq 0 at device 6.0 on pci0
	dc0: interrupting at CIA irq 0
	dc0: Ethernet address: 08:00:2b:c5:3b:2d
	miibus0: <MII bus> on dc0
	dcphy0: <Intel 21143 NWAY media interface> on miibus0
	dcphy0:  10baseT, 10baseT-FDX, 100baseTX, 100baseTX-FDX, auto
	sym0: <875> port 0x1000-0x10ff mem 0x82270000-0x82270fff,0x82271000-0x822710ff irq 1 at device 7.0 on pci0
	sym0: Symbios NVRAM, ID 7, Fast-20, SE, parity checking
	sym0: open drain IRQ line driver, using on-chip SRAM
	sym0: interrupting at CIA irq 1
	isab0: <Intel 82378IB PCI to ISA bridge> at device 8.0 on pci0
	isa0: <ISA bus> on isab0
	pci0: <Trident model 9440 VGA-compatible display device> at 9.0 irq 3
	pci0: <CMD 646 ATA controller> at 11.0 irq 5
	mcclock0: <MC146818A real time clock> at port 0x70-0x71 on isa0
	atkbdc0: <Keyboard controller (i8042)> at port 0x60,0x64 on isa0
	atkbd0: <AT Keyboard> irq 1 on atkbdc0
	atkbd0: interrupting at ISA irq 1
	psm0: <PS/2 Mouse> irq 12 on atkbdc0
	psm0: interrupting at ISA irq 12
	psm0: model Generic PS/2 mouse, device ID 0
	vga0: <Generic ISA VGA> at port 0x3c0-0x3df iomem 0xa0000-0xbffff on isa0
	sc0: <System console> on isa0
	sc0: VGA <16 virtual consoles, flags=0x200>
	fdc0: <NEC 72065B or clone> at port 0x3f0-0x3f5,0x3f7 irq 6 drq 2 on isa0
	fdc0: interrupting at ISA irq 6
	fdc0: FIFO enabled, 8 bytes threshold
	fd0: <1440-KB 3.5" drive> on fdc0 drive 0
	sio0 at port 0x3f8-0x3ff irq 4 on isa0
	sio0: type 16550A
	sio0: interrupting at ISA irq 4
	sio1: reserved for low-level i/o
	Timecounter "alpha"  frequency 533180608 Hz
	IPsec: Initialized Security Association Processing.
	Waiting 2 seconds for SCSI devices to settle
	(noperiph:sym0:0:-1:-1): SCSI BUS reset delivered.
	Mounting root from ufs:/dev/da0f
	cd0 at sym0 bus 0 target 5 lun 0
	cd0: <TOSHIBA CD-ROM XM-6401TA 1015> Removable CD-ROM SCSI-2 device 
	cd0: 20.000MB/s transfers (20.000MHz, offset 16)
	cd0: Attempt to query device size failed: NOT READY, Medium not present
	da1 at sym0 bus 0 target 1 lun 0
	da1: <IBM DNES-309170W SAH0> Fixed Direct Access SCSI-3 device 
	da1: 40.000MB/s transfers (20.000MHz, offset 16, 16bit), Tagged Queueing Enabled
	da1: 8748MB (17916240 512 byte sectors: 255H 63S/T 1115C)
	da0 at sym0 bus 0 target 0 lun 0
	da0: <IBM DDRS-39130D DC1B> Fixed Direct Access SCSI-2 device 
	da0: 40.000MB/s transfers (20.000MHz, offset 15, 16bit), Tagged Queueing Enabled
	da0: 8715MB (17850000 512 byte sectors: 255H 63S/T 1111C)