Re: No serial ports found after 2.6 kernel upgrade

[Tony Terlecki <lists@tonyterlecki.co.uk>]

On Sun, May 07, 2006 at 12:56:18PM +0200, Martin A. Brooks wrote:
> Tony Terlecki wrote:
> >Maybe there is something outside of the serial drivers support I need to
> >include in the kernel build?
> 
> I'm running 2.6.15 with the following serial options:
> 
> myth:~# grep SERIAL /usr/src/linux/.config
> # CONFIG_SERIAL_NONSTANDARD is not set
> CONFIG_SERIAL_8250=y
> CONFIG_SERIAL_8250_CONSOLE=y
> CONFIG_SERIAL_8250_NR_UARTS=4
> CONFIG_SERIAL_8250_RUNTIME_UARTS=4
> CONFIG_SERIAL_8250_EXTENDED=y
> # CONFIG_SERIAL_8250_MANY_PORTS is not set
> CONFIG_SERIAL_8250_SHARE_IRQ=y
> # CONFIG_SERIAL_8250_DETECT_IRQ is not set
> # CONFIG_SERIAL_8250_RSA is not set
> CONFIG_SERIAL_CORE=y
> CONFIG_SERIAL_CORE_CONSOLE=y
> # CONFIG_SERIAL_JSM is not set
> 
> You don't mention if you're compiling these options statically or as 
> modules.  If it's the latter, are you sure the modules are loading?
> 

Thanks for the pointer.

Some were static and some were loaded via modules. I've recompiled with
all of them statically in the kernel and that seems to have done the
trick. For some reason I thought that the modules would have been
automatically loaded on boot when probing for serial ports (shows how
little I know about module behaviour)!

Strangely now it is showing 4 serial ports although there are only 2 via
IRQ4 and IRQ3. Any idea why it is reporting this?

Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing enabled
serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
serial8250: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A
serial8250: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
serial8250: ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A

Cheers,

-- 
Tony Terlecki
lists@tonyterlecki.co.uk