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Re: Serial Port Bug?



On Wednesday 28 November 2007, Karl Larsen wrote:
> Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing enabled
>
> Nothing about being set up in dmesg. It appears the kernel correctly
> sees the driver. But for some reason it is not turned on.

If the kernel's serial driver sees a serial port enabled it will print three 
lines (not just one) like this:
Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing enabled
serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
00:07: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A

On my F8 laptop, which has no serial ports, I still get:
Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing enabled

but no actual ports are found.  Just because the kernel loads the serial 
driver doesn't mean it saw a serial port.

So I ask again: is your serial port enabled or disabled in the BIOS?  All 
modern BIOS's have the capability to disable the serial ports in hardware to 
where the kernel will not see the ports.

Checking voltages won't help you if the chip interface has been disabled from 
the BIOS setup program.
-- 
Lamar Owen
Chief Information Officer
Pisgah Astronomical Research Institute
1 PARI Drive
Rosman, NC  28772
(828)862-5554
www.pari.edu


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