On 18 March 2014 11:30, Wolfgang Denk wd@denx.de wrote:
Dear Andrew,
In message <
CAPcvp5FNJo9y3mKhUdgar1jx0tfHkeXU06BbTg5NCCSQ3Wb_uQ@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