On Sunday 03 June 2007, Andrey Borzenkov wrote:
> Under 2.6.22-rc I lost irda0 interface - smsc claims no device present.
> Nothing was changed in setup except kernel version.
>
> 2.6.21:
>
> Detected unconfigured Toshiba laptop with ALi ISA bridge SMSC IrDA chip,
> pre-configuring device.
> Activated ALi 1533 ISA bridge port 0x02e8.
> Activated ALi 1533 ISA bridge port 0x02f8.
> found SMC SuperIO Chip (devid=0x5a rev=00 base=0x002e): LPC47N227
> smsc_superio_flat(): IrDA not enabled
> smsc_superio_flat(): fir: 0x2f8, sir: 0x2e8, dma: 03, irq: 7, mode: 0x02
> SMsC IrDA Controller found
>  IrCC version 2.0, firport 0x2f8, sirport 0x2e8 dma=3, irq=7
> No transceiver found. Defaulting to Fast pin select
> IrDA: Registered device irda0
>
>
> 2.6.22-rc3:
> Detected unconfigured Toshiba laptop with ALi ISA bridge SMSC IrDA chip,
> pre-configuring device.
> Activated ALi 1533 ISA bridge port 0x02e8.
> Activated ALi 1533 ISA bridge port 0x02f8.
> pnp: Device 00:0a activated.
> smsc_ircc_present(), addr 0x02e8 - no device found!
> pnp: Device 00:0a disabled.
>
> I Cc Adam because of pnp messages in this case - they were not present in
> 2.6.21 so something is being done differently now.
>
> Some more info:
>
> {pts/1}% cat /sys/bus/pnp/devices/00:0a/id
> SMCf010
> {pts/1}% lspci -nn
> 00:00.0 Host bridge [0600]: ALi Corporation M1644/M1644T
> Northbridge+Trident [10b9:1644] (rev 01)
> 00:01.0 PCI bridge [0604]: ALi Corporation PCI to AGP Controller
> [10b9:5247] 00:02.0 USB Controller [0c03]: ALi Corporation USB 1.1
> Controller [10b9:5237] (rev 03)
> 00:04.0 IDE interface [0101]: ALi Corporation M5229 IDE [10b9:5229] (rev
> c3) 00:06.0 Multimedia audio controller [0401]: ALi Corporation M5451 PCI
> AC-Link Controller Audio Device [10b9:5451] (rev 01)
> 00:07.0 ISA bridge [0601]: ALi Corporation M1533/M1535 PCI to ISA Bridge
> [Aladdin IV/V/V+] [10b9:1533]
> 00:08.0 Bridge [0680]: ALi Corporation M7101 Power Management Controller
> [PMU] [10b9:7101]
> 00:0a.0 Ethernet controller [0200]: Intel Corporation 82557/8/9 [Ethernet
> Pro 100] [8086:1229] (rev 08)
> 00:10.0 CardBus bridge [0607]: Texas Instruments PCI1410 PC card Cardbus
> Controller [104c:ac50] (rev 01)
> 00:11.0 CardBus bridge [0607]: Toshiba America Info Systems ToPIC100 PCI to
> Cardbus Bridge with ZV Support [1179:0617] (rev 32)
> 00:11.1 CardBus bridge [0607]: Toshiba America Info Systems ToPIC100 PCI to
> Cardbus Bridge with ZV Support [1179:0617] (rev 32)
> 00:12.0 System peripheral [0880]: Toshiba America Info Systems SD TypA
> Controller [1179:0805] (rev 03)
> 01:00.0 VGA compatible controller [0300]: Trident Microsystems CyberBlade
> XPAi1 [1023:8820] (rev 82)
>
> config from 2.6.22-rc3 attached.
>

Adding "nopnp" parameters finds device just fine so it is apparently result of 
this commit:

commit d0d4f69bb65a8c1c1430c577a583632709b874c6
Author: Bjorn Helgaas <bjorn.helgaas@hp.com>
Date:   Tue May 8 00:36:05 2007 -0700

    smsc-ircc2: add PNP support

What information is needed to debug it further?

-andrey