Re: [PATCH 2/2] tty: serial: 8250_core: Check that port->line is >=0

[Sebastian Andrzej Siewior <bigeasy@linutronix.de>]

On 01/16/2015 12:02 PM, Michal Simek wrote:
>>> Origin patch looks good to me but this checking will be good to add.
>>> Are you using of_serial.c because I didn't find any of_alias_get_id call
>>> for 8250?
>>
>> I'm using of_alias_get_id() in 8250_omap.c which made it into
>> v3.19-rc1. I think the change you mention made it one release earlier.
> 
> I see
> serial: of-serial: fetch line number from DT
> commit 1bd8324535ec1ff44aef55c0e40b9e7d56b310fb
> 
> but it was reverted
> 
> Revert "serial: of-serial: fetch line number from DT"
> commit e4c787dac21e50ac9ef53fac91b9182d4fede465
> 
> Olof: what was the reason for that breakage?
> Is it missing alias list on Tegra?
> which caused that port->line number is bogus.

I doubt it, because a missing alias would return -1 and would not be
considered for port->line.

I think it is more what happens if you use the second UART and the
primary is unused (as in not probed). With this change the console will
be on ttyS1 - without it it remains on ttyS0. The former is what we
wanted.

And it seems they use for "nvidia,tegra[23]0-hsuart" the serial-tegra.c
driver which makes use of of_alias_get_id() but the of_serial() one
which is used by nvidia,tegra20-uart() does not. And since this change
does not notify anyone during upgrade but removes the console everyone
gets a little grumpy*.

* and I've been looking for a smooth solution for the ttyOx -> ttySx
  change in OMAP just to avoid people complaining and risking a revert
  :)

> Thanks,
> Michal

Sebastian