Messages in this thread | | | Date | Wed, 13 Aug 2003 12:16:47 -0400 (EDT) | From | "Richard B. Johnson" <> | Subject | Re: Bogus serial port ttyS02 |
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On Wed, 13 Aug 2003, Geert Uytterhoeven wrote:
> > Linux always finds 3 serial ports instead of 2: > > | ttyS00 at 0x03f8 (irq = 4) is a 16550A > | ttyS01 at 0x02f8 (irq = 3) is a 16550A > | ttyS02 at 0x03e8 (irq = 4) is a 16450 > > The last one is bogus.
First, this looks like ix86 stuff, not m68k. Drivers for ix86 machines probe the de facto addresses for up to a maximum of 4 8250-type UARTS. Those addresses are:
(0) 0x3f8 (1) 0x2f8 (2) 0x3e8 (3) 0x328
(from the Phoenix SYSTEM BIOS book)
Usually, there are several bits that are permanently 0 in some of the registers. This is used to "positively" identify the chip. Note that many IR devices are also connected to 8250-type UARTS.
I would guess that you have two serial ports, plus another UART that's used for IR (maybe a IR keyboard???).
You can do `od /dev/ttyS2` from the root account and see what happends.
Cheers, Dick Johnson Penguin : Linux version 2.4.20 on an i686 machine (797.90 BogoMips). Note 96.31% of all statistics are fiction.
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