Re: earlycon: no match?

[Peter Hurley <peter@hurleysoftware.com>]

On 05/07/2015 01:09 PM, Maciej W. Rozycki wrote:
> On Mon, 4 May 2015, Peter Hurley wrote:
> 
>>>> Since 2007, 'console=' is a early param synonym for 'earlycon='; IOW,
>>>> the message is new but not the behavior.
>>>
>>> "console=" had nothing to do with early param before.
>>
>> *Yes, it has* since the commit I referenced in the previous email and
>> the email before that when I noted that 'console=' and 'earlycon=' are
>> synonyms if CONFIG_SERIAL_EARLYCON=y, and it has been that way since
>> 2007.
>>
>> The only thing that has changed is that I added a diagnostic; _to repeat_,
>> the earlycon matching code has always run in this case, only the
>> diagnostic is new.
> 
>  What's the point of having two parameters as synonyms whose syntax is not 
> compatible to each other in the general case?  I'd expect the following 
> cases to be handled:
> 
> 1. Regular console only (no early console requested) => `console=foo...'.
> 
> 2. Both early and regular console => `earlycon=blah... console=foo...'.
> 
> 3. Early console handing over to regular console => `earlycon=blah...'.

  4. Early console only => `earlycon=blah...'

How to distinguish between 3 & 4?

> Why do you want to support `console=blah...' too (a question to be asked 
> back in 2007, but better late than never)?

Command line is considered to be userspace, so it doesn't really matter
what I think about whether console= should have been overloaded like that.

The fact is, it was.


>  If you do need to support such aliasing, then I suggest that you complain 
> about no early console match only if `earlycon=blah...' has been truly 
> used and avoid the warning where `console=blah...' has been used instead 
> (a warning about the latter can be issued where no regular console match 
> happened).

I'm tearing it out;  I'd prefer to go back to the old way where you
don't know why your earlycon didn't start, and I don't get emails
complaining about logs.

Regards,
Peter Hurley