Configuration:
Red Hat 7.1 distribution, 256MB memory, Dell Optiplex
lspci reports the modem as follows:
02:09.0 Serial controller: US Robotics/3Com 56K FaxModem Model 5610 (rev 01)
(prog-if 02 [16550])
Subsystem: US Robotics/3Com: Unknown device 00d7
Control: I/O+ Mem- BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR+ FastB2B-
Status: Cap+ 66Mhz- UDF- FastB2B- ParErr- DEVSEL=medium >TAbort- <TAbort-
<MAbort- >SERR- <PERR-
Interrupt: pin A routed to IRQ 5
Region 0: I/O ports at dcf8 [size=8]
Capabilities: [dc] Power Management version 2
Flags: PMEClk- DSI- D1- D2+ AuxCurrent=0mA PME(D0+,D1-,D2+,D3hot+,D3cold-)
Status: D0 PME-Enable- DSel=0 DScale=2 PME-
I have the modem configured as /dev/ttyS2. The system has two real serial
ports at ttyS0 and ttyS1. /dev/modem is a link to /dev/ttyS2.
setserial reports as follows on 2.4.2:
/dev/ttyS2, UART: 16550A, Port: 0xdcf8, IRQ: 5
On 2.4.10 setserial reports as follows instead:
/dev/ttyS2, UART: unknown, Port: 0x03e8, IRQ: 4
I can change the uart type and IRQ settings just fine, to match those
shown on 2.4.2. But when I use setserial to change the IO port address
to 0xdcf8 on 2.4.10 I get a message that the address is already in use.
Another clue is when rebooting from one kernel to the other a KUDZU
window appears saying that the modem has been removed and do I want to
change the configuration. I always say keep the old configuration.
The modem continues to work just fine on 2.4.2.
A further clue is the following "Multimedia" device reported by lspci.
Note the IO port addresses:
02:0b.0 Multimedia controller: CMD Technology Inc PCI0647 (prog-if 8f)
Subsystem: CMD Technology Inc PCI0647
Control: I/O+ Mem- BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR- FastB2B-
Status: Cap- 66Mhz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort-
<MAbort- >SERR- <PERR-
Latency: 64 (500ns min, 1000ns max)
Interrupt: pin A routed to IRQ 5
Region 0: I/O ports at dcf0 [size=8]
Region 1: I/O ports at dce8 [size=4]
Region 2: I/O ports at dcd8 [size=8]
Region 3: I/O ports at dcd0 [size=4]
Region 4: I/O ports at dcb0 [size=16]
The Region 0 port at dcf0, plus its size of 8 is dcf8, where the modem is.
Does 2.4.10 think that dcf0+8 is using dcf8 where 2.4.2 does not?
The only difference in the lspci listings is as follows. The entry for
an Intel Bridge chip actually has an additional line in it on 2.4.10, the
last line below showing "pin ? routed to IRQ 9". Since the hardware
is identical for both boots, I would think the lspci listings to be
identical.
00:07.3 Bridge: Intel Corporation 82371AB PIIX4 ACPI (rev 02)
Control: I/O+ Mem- BusMaster- SpecCycle- MemWINV- VGASnoop- ParErr-
Stepping- SERR- FastB2B-
Status: Cap- 66Mhz- UDF- FastB2B+ ParErr- DEVSEL=medium >TAbort- <TAbort-
<MAbort- >SERR- <PERR-
Interrupt: pin ? routed to IRQ 9
-pd
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