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

Ruud Linders (rkmp@xs4all.nl)
Tue, 3 Jun 2003 18:58:15 +0200


Paul,

Setting SERIAL_DEBUG_PCI gives me this:

Serial: 8250/16550 driver $Revision: 1.90 $ IRQ sharing enabled
ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A
ttyS1 at I/O 0x2f8 (irq = 3) is a 16550A
Setup PCI port: port bc00, irq 21, type 0
ttyS14 at I/O 0xbc00 (irq = 21) is a 16550A
Setup PCI port: port bc08, irq 21, type 0
ttyS15 at I/O 0xbc08 (irq = 21) is a 16550A
Setup PCI port: port bc10, irq 21, type 0
ttyS2 at I/O 0xbc10 (irq = 21) is a 16550A
Setup PCI port: port bc18, irq 21, type 0
ttyS3 at I/O 0xbc18 (irq = 21) is a 16550A

Doesn't give us much more detail.

BTW, this is the entry in 8250_pci.c for the board in question:
{ PCI_VENDOR_ID_PLX, PCI_DEVICE_ID_PLX_1077,
PCI_ANY_ID, PCI_ANY_ID, 0, 0,
pbn_b2_4_921600 },

Note that the ttyS's _are_ numbered in sequence in 2.4.20

On Mon, Jun 02, 2003 at 08:43:24PM +0200, Paul Rolland wrote:
> Hello,
>
>
> > 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 :
> #ifdef SERIAL_DEBUG_PCI
> printk("Setup PCI port: port %x, irq %d, type %d\n",
> serial_req.port, serial_req.irq, serial_req.io_type);
> #endif
>
> that would report to you the order in which ports are found on
> your system.
>
> Regards,
> Paul
>
>
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