Hi all,
I noticed the sc26xx driver uses ttySC205 / ttySC206 for device name.
grep ttySC Documentation/devices.txt gives
8 = /dev/ttySC0 SCI serial port (SuperH) - port 0
9 = /dev/ttySC1 SCI serial port (SuperH) - port 1
10 = /dev/ttySC2 SCI serial port (SuperH) - port 2
11 = /dev/ttySC3 SCI serial port (SuperH) - port 3
205 = /dev/ttySC0 SC26xx serial port 0
206 = /dev/ttySC1 SC26xx serial port 1
207 = /dev/ttySC2 SC26xx serial port 2
208 = /dev/ttySC3 SC26xx serial port 3
8 = /dev/cusc0 Callout device for ttySC0
9 = /dev/cusc1 Callout device for ttySC1
10 = /dev/cusc2 Callout device for ttySC2
11 = /dev/cusc3 Callout device for ttySC3
Removing the line:
sc26xx_reg.tty_driver->name_base = sc26xx_reg.minor;
makes it revert to ttySC0
So two questions:
1) Who is right (the driver or devices.txt)?
2) How are device name conflicts handled?
Cheers,
Martin
> So two questions:
> 1) Who is right (the driver or devices.txt)?
devices.txt has all the officially properly registered values
> 2) How are device name conflicts handled?
Badly - they should never occur but if someone didn't properly reserve
the namespace they can and then whoever forgot to reserve the namespace
loses.
Alan Cox wrote:
>> 2) How are device name conflicts handled?
>>
>
> Badly - they should never occur but if someone didn't properly reserve
> the namespace they can and then whoever forgot to reserve the namespace
> loses.
>
Currently this can't happen because the sc26xx driver uses ttySC205
in contradiction to ttySC0 shown in devices.txt
However if the driver were to be "fixed" to use the name registered
in devices.txt a conflict could occur if a sc26xx chip were used on
a superH system.
The problem seems to be that while the major/minor numbers in devices.txt
are unique (and the drivers are correctly using their registered numbers),
the _names_ are not unique (at least in this case - I haven't checked for
others).
On Sat, 21 Nov 2009 15:23:32 +0100
Martin Fuzzey <[email protected]> wrote:
> Alan Cox wrote:
> >> 2) How are device name conflicts handled?
> >>
> >
> > Badly - they should never occur but if someone didn't properly reserve
> > the namespace they can and then whoever forgot to reserve the namespace
> > loses.
> >
> Currently this can't happen because the sc26xx driver uses ttySC205
> in contradiction to ttySC0 shown in devices.txt
I'd suggest that someone fixes it when it happens in that case. I doubt
it ever will.