Re: Serial port numbering (ttyS..) wrong for 2.5.61+

From: Paul Rolland (
Date: Mon Jun 02 2003 - 13:43:24 EST


> When we add a port to the system, we try to find in order:
> - a port which matches the base address
> - a port which is unallocated
> Probably the easiest way to stop the "ttyS14" occuring would
> be to clear the port information at boot when we don't find a port.
>From 8250_pci.c, you have :

 * Probe one serial board. Unfortunately, there is no rhyme nor reason
 * to the arrangement of serial ports on a PCI card.

It seems that your board is reporting the parameters in such an order
that when looking for a port based on the IRQ, I/O port, ... the matching
one has id 14...

You could see this more clearly by setting SERIAL_DEBUG_PCI
at line 1549 to activate the code :
                printk("Setup PCI port: port %x, irq %d, type %d\n",
                       serial_req.port, serial_req.irq, serial_req.io_type);

that would report to you the order in which ports are found on
your system.


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This archive was generated by hypermail 2b29 : Sat Jun 07 2003 - 22:00:17 EST