[U-Boot] [RFC 1/2] env: Drop error messages when loading environment

[Sam Protsenko]

On Wed, Jul 18, 2018 at 9:19 AM, Wolfgang Denk <wd at denx.de> wrote:
> Dear Sam,
>
> In message <20180717220912.11358-1-semen.protsenko at linaro.org> you wrote:
>> This is just a draft to discuss ideas related to "Make U-Boot log great
>> again" thread.
>>
>> With this patch we will have something like this:
>>
>>     Loading Environment from FAT... Failed (-5)
>>     Loading Environment from MMC... OK
>>
>> instead of this:
>>
>>     Loading Environment from FAT... MMC: no card present
>>     ** Bad device mmc 0 **
>>     Failed (-5)
>>     Loading Environment from MMC... OK
>
> Why do you think an error message "Failed (-5)" looks great?
>

As I mentioned in commit message, this RFC series is merely for
discussing ideas. I don't think it's "great" (for the same reasons you
mentioned), but this is one of things we *could* do technically, to
make boot log straight. What I mean "technically" doable: for example
we would like to see log like this:

    Loading Environment from FAT... Failed (-5):
       -> MMC: no card present
       -> ** Bad device mmc 0 **
    Loading Environment from MMC... OK

But to do so, we would probably need to do one of these:
  1. Rework the code for all boot sources (like drivers/mmc/mmc.c), so
that that code doesn't print warnings to console, but instead filling
some error buffer, so we can print that buffer later from env.c. I'm
not sure it's a sane idea
  2. Issuing some escape codes for moving cursor up and down, to
modify already printed message, also has a lot of implications and I
don't thing it's sane as well...
  3. Messing with GD_FLG_RECORD and GD_FLG_SILENT also doesn't seem to
be right here, as much of platforms don't enable CONFIG_CONSOLE_RECORD
and CONFIG_SILENT_CONSOLE

So *technically*, we can only do what I did in two RFC patches I sent.
The only other way I see, is to make boot log look like this:

    --> Loading Environment from FAT... MMC: no card present
    ** Bad device mmc 0 **
    Failed (-5):
    --> Loading Environment from MMC... OK

Not sure if I like this way, but it's doable.

If you have any preferences about what I said, or if you have any
other ideas on how to approach this, please share. That's the whole
reason why I sent this RFC series :)

> From a user's point of view, the "MMC: no card present"
> is _much_ better (but of course it could still be improved).
>
> Printing cryptic error codes has never been a good idea and is
> definitly not a "great" idea.
>
> Best regards,
>
> Wolfgang Denk
>
> --
> DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
> Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
> Fools ignore complexity. Pragmatists suffer it. Some  can  avoid  it.
> Geniuses remove it.
>      - Perlis's Programming Proverb #58, SIGPLAN Notices, Sept.  1982