A major:minor collision in 2.6.15

[Alon Keren]

On 2/14/06, Russell King <rmk+pcmcia at arm.linux.org.uk> wrote:
> On Tue, Feb 14, 2006 at 11:05:35AM +0200, Alon Keren wrote:
> > On 2/14/06, Russell King <rmk+pcmcia at arm.linux.org.uk> wrote:
> > > On Tue, Feb 14, 2006 at 09:48:57AM +0200, Alon Keren wrote:
> > > > On 2/14/06, Russell King <rmk+pcmcia at arm.linux.org.uk> wrote:
> > > > > On Mon, Feb 13, 2006 at 09:30:55PM +0200, Alon Keren wrote:
> > > > > > I have the following setup:
> > > > > > Kernel: 2.6.15
> > > > > > pcmciautils-012
> > > > > > PCMCIA-card: Advantech's COMpad-32/85
> > > > > >
> > > > > > For some reason, my card seems to be in conflict with another card (an
> > > > > > old V.34 modem) for the same major:minor numbers - 4:65.
> > > > >
> > > > > Please provide the contents of /proc/tty/driver/serial for each of these
> > > > > cases.  Thanks.
> > > > >
> > > >
> > > > The contents of '/proc/tty/driver/serial' in the 2.6.15 machine:
> > > > When NO cards are in:
> > > >
> > > >         serinfo:1.0 driver revision:
> > > >         0: uart:16550A port:000003F8 irq:4 tx:0 rx:0
> > > >         1: uart:unknown port:00004338 irq:3
> > > >         2: uart:16550A port:000003E8 irq:4 tx:0 rx:0
> > > >         3: uart:unknown port:00004330 irq:3
> > >
> > > Okay, so two ports were detected at boot time, and the driver is
> > > configured to have a maximum of four ports.  You're trying to add
> > > three additional ports, at least one has to fail.
> > >
> > > > The file's contents in the 2.6.11 machine, when the COMpad is inserted first:
> > > >
> > > >       serinfo:1.0 driver revision:
> > > >       0: uart:16550A port:000003F8 irq:4 tx:0 rx:0
> > > >       1: uart:16550A port:000002F8 irq:5 tx:0 rx:0 CTS|DSR
> > > >       2: uart:16550A port:000003E8 irq:4 tx:0 rx:0
> > > >       3: uart:unknown port:000002E8 irq:3
> > > >       4: uart:unknown port:000001A0 irq:9
> > > >       5: uart:unknown port:000001A8 irq:9
> > > >       6: uart:unknown port:000001B0 irq:9
> > > >       7: uart:unknown port:000001B8 irq:9
> > >
> > > whereas this one has a maximum of 48 ports configured.
> > >
> > > Check the setting of CONFIG_SERIAL_8250_NR_UARTS and (if you have it)
> > > CONFIG_SERIAL_8250_RUNTIME_UARTS.
> >
> > 'CONFIG_SERIAL_8250_NR_UARTS' is set to "4" on both the 2.6.11 and the
> > 2.6.15 machines.
>
> You are mistaken - there's absolutely no way what so ever that it could
> have been set to 4 in the kernel you supplied the /proc/tty/driver/serial
> from.  With 2.6.15 and earlier, you will always get exactly
> CONFIG_SERIAL_8250_NR_UARTS "uart" lines in /proc/tty/driver/serial,
> no ifs or buts.
>

#> uname -r
2.6.11.12
#> zcat /proc/config.gz | grep UARTS
CONFIG_SERIAL_8250_NR_UARTS=4
#> cat  /proc/tty/driver/serial | wc -l
49
----------------------------------------------------------------


> Please set CONFIG_SERIAL_8250_NR_UARTS to a more reasonable value for
> your requirements.
>

Both are accesible now. Many thanks.

- Alon