Can I force PIO mode 3?

[Michael H Buselli <cosine_(_at_)_computer_(_dot_)_org>]

Hello,

I'm having a problem accessing my IDE CD-ROM.  The problem seems to be
that for some reason the driver is trying to use PIO mode 0 for its
first attempt at the drive, and that doesn't work.  Eventually (anywhere
between 2 minutes and 45 minutes), the driver downgrades to PIO mode 3
and the CD-ROM works fine until the next reboot.

I would like to know how to force PIO mode 3 on the first attempt.  Just
in case it helps, here's my dmesg output with my comments in there
between the square brackets ([[ ]]).  The kernel was recompiled to help
with the CD-ROM issue, but it didn't really improve it.  I'm using 2.7
base, not current, so please let me know if updating myself to current
would help (it's a lot of trouble for me).  My first IDE bus has only
one hard drive, and my second IDE bus has only this CD-ROM.

--
OpenBSD 2.7 (INDIA) #0: Mon Jan  1 23:55:00 CST 1996
    secant_(_at_)_india:/usr/src/sys/arch/i386/compile/INDIA
cpu0: F00F bug workaround installed
cpu0: Intel Pentium (P54C) ("GenuineIntel" 586-class) 166 MHz
cpu0: FPU,V86,DE,PSE,TSC,MSR,MCE,CX8
real mem  = 66699264 (65136K)
avail mem = 58200064 (56836K)
using 839 buffers containing 3436544 bytes (3356K) of memory
mainbus0 (root)
bios0 at mainbus0: AT/286+(00) BIOS, date 07/15/95
apm0 at bios0: Power Management spec V1.2
apm0: AC on, battery charge unknown
pci0 at mainbus0 bus 0: configuration mode 1 (bios)
pchb0 at pci0 dev 0 function 0 "Intel 82439HX (Triton II) TXC Host" rev 0x01
pcib0 at pci0 dev 7 function 0 "Intel 82371SB (Triton II) PCI-ISA" rev 0x00
pciide0 at pci0 dev 7 function 1 "Intel 82371SB (Triton II) IDE" rev 0x00: DMA,
channel 0 wired to compatibility, channel 1 wired to compatibility
wd0 at pciide0 channel 0 drive 0: <Maxtor 51536U3>
wd0: can use 32-bit, PIO mode 4, DMA mode 2
wd0: 16-sector PIO, LBA, 14655MB, 16383 cyl, 16 head, 63 sec, 30015216 sectors
pciide0: channel 0 interrupting at irq 14
wd0(pciide0:0:0): using PIO mode 4, DMA mode 2 (using DMA data transfers)

	[[ Now the kernel gets around to finding the CD. ]]

atapiscsi0 at pciide0 channel 1
scsibus0 at atapiscsi0: 2 targets

	[[ Below are some messages that may be related. ]]

pciide0:1:0: IDENTIFY timed out
pciide0:1:0: Post IDENTIFY timed out
pciide0:1:0: Post IDENTIFY timed out
pciide0:1:0: Post IDENTIFY timed out
probe(atapiscsi0:0:0): Check Condition on opcode 0
    SENSE KEY: Aborted Command
cd0 at scsibus0 targ 0 lun 0: <GoldStar, CD-ROM GCD-R580B, 1.00> SCSI0 5/cdrom r
emovable
cd0: can use 32-bit, PIO mode 3, DMA mode 1

	[[ The last two lines above look good.  PIO mode 3 works. ]]

pciide0: channel 1 interrupting at irq 15
cd0(pciide0:1:0): using PIO mode 0, DMA mode 1 (using DMA data transfers)

	[[ It switched to PIO mode 0 somewhere.  This won't work. ]]

dc0 at pci0 dev 9 function 0 "Lite-On PNIC" rev 0x20: irq 10 address 00:a0:cc:26
:f6:37
ukphy0 at dc0 phy 1: Generic IEEE 802.3u media interface
ukphy0: OUI 0x00c0b4, model 0x0000, rev. 8
"S3 Trio32/64" rev 0x40 at pci0 dev 10 function 0 not configured
isa0 at pcib0
isadma0 at isa0
: timeout in getresult
: timeout in getresult
: timeout in getresult

	[[ I suspect the last three lines are also related to the CD. ]]

pcppi0 at isa0 port 0x61
midi0 at pcppi0: <PC speaker>
sysbeep0 at pcppi0
lpt0 at isa0 port 0x378/4 irq 7
npx0 at isa0 port 0xf0/16: using exception 16
pccom0 at isa0 port 0x3f8/8 irq 4: ns16550a, 16 byte fifo
pccom1 at isa0 port 0x2f8/8 irq 3: ns16550a, 16 byte fifo
vt0 at isa0 port 0x60/16 irq 1: vga 80 col, color, 8 scr, mf2-kbd
fdc0 at isa0 port 0x3f0/6 irq 6 drq 2
fd0 at fdc0 drive 0: 1.44MB 80 cyl, 2 head, 18 sec
isapnp0 at isa0 port 0x279: read port 0x203
"33.6Modem, ROK4120, , " at isapnp0 port 0x3e8/8 irq 5 not configured
biomask c040 netmask c440 ttymask c4c2
pctr: 586-class performance counters and user-level cycle counter enabled
dkcsum: wd0 matched BIOS disk 80
root on wd0a
rootdev=0x0 rrootdev=0x300 rawdev=0x302

	[[ System is up now.  If I access the CD now, I must wait and ]]
	[[ eventually I am treated to this addition to my dmesg. ]]

cd0(pciide0:1:0): timeout
        type: atapi
        c_bcount: 32
        c_skip: 0
pciide0:1:0: device timeout, c_bcount=32, c_skip=0
cd0: transfer error, downgrading to PIO mode 3
cd0(pciide0:1:0): using PIO mode 3
cd0(atapiscsi0:0:0): Check Condition on opcode 43
    SENSE KEY: Unit Attention

	[[ And now the CD works until next reboot. ]]
--

If this is just a matter of adding support in the kernel for my
particular CD-ROM, then I'd love to use this as an excuse to learn how
to hack device drivers.  I can't imagine that this is the case, though,
because in OpenBSD 2.4 when this CD-ROM was acd0 it worked fine.

Thank you for any help you can give me.

T\_/T\_/T
Michael Buselli [http://www.enteract.com/~cosine/] <cosine_(_at_)_computer_(_dot_)_org>
"Take that unix admin tool and strike me down with all of your hate, and
 your journey towards the dark side will be complete."  --Carl Molyneaux