[U-Boot] Antw: Re: U-Boot doesn't silent the output

[Andrew Murray]

On 18 March 2014 11:30, Wolfgang Denk <wd at denx.de> wrote:
> Dear Andrew,
>
> In message <
CAPcvp5FNJo9y3mKhUdgar1jx0tfHkeXU06BbTg5NCCSQ3Wb_uQ at mail.gmail.com> you
wrote:
>>
>> If I remember, fixup_silent_linux ensures that 'console=' is present
>> in the kernel arguments (i.e. it will replace console=/dev/ttyS0 (or
>> similar) with console=).
>>
>> I think preferred behavior for this may be to instead leave any
>> 'console' arguments as they are and instead ensure that 'quiet' or
>> 'loglevel=1' is present instead. There are two motivations for doing
>> this - the first is that when using a lower loglevel you still get
>> suppressed kernel output - but you also get any errors. Thus if
>> something goes wrong you'll see why rather than wonder if U-Boot even
>> started the kernel. The second is that I've seen a few times in the
>> past where setting console to nothing (console=) results in strange
>> behavior (it once increased boot time). After all we want a console we
>> just don't want to use it as much. I can provide a patch for this if
>> you think you may take it?
>
> I have to admit that I don't know if this is a good idea. I do know
> that some users use this feature to make sure the console port is
> completely free, and no characters ever are sent to it, for example
> because they use it for application specific purposes. Of course one
> might ask if this is a good idea (IMO a separate console port is a
> very useful feature), but you know how some companies design their
> hardware...

Yes I can understand why they would want to do that.

However I would argue that using the 'silent' feature isn't the correct way
to achieve it. If a user depends on having a console completely free then
they probably shouldn't add a 'console=xyz' to their boot args in the first
place.

Thanks,

Andrew Murray