[U-Boot] [PATCH 1/3] test/py: Handle the banner being printed after relocation

[Stephen Warren]

On 07/27/2017 09:31 AM, Simon Glass wrote:
> If CONFIG_DISPLAY_BOARDINFO_LATE is enabled, U-Boot displays the banner
> again after relocation so that it is visible on the video display. Detect
> this and allow it.
> 
> Note: This patch is only an interim fix. If it is applied we should
> consider reverting it later since it is not needed if U-Boot is working
> correctly.

It'd be useful if that paragraph could be expanded a bit; what exactly 
is the bug and how will it be fixed? The situation described in the 
first paragraph doesn't seem like a bug. Perhaps the fix be to delay the 
sign-on message until video output is available and only print it once, 
or not print the sign-on to serial when printing it a second time so 
that it's seen on video?

> diff --git a/test/py/u_boot_console_base.py b/test/py/u_boot_console_base.py

> @@ -355,12 +355,31 @@ class ConsoleBase(object):
>               self.u_boot_version_string = self.p.after
>               while True:
>                   m = self.p.expect([self.prompt_compiled,
> -                    pattern_stop_autoboot_prompt] + self.bad_patterns)
> +                    pattern_stop_autoboot_prompt, pattern_u_boot_main_signon] +
> +                    self.bad_patterns)

This doesn't seem quite right. At a very high level, the current code 
does this:

1) If SPL will print a sign-on:
      Wait for SPL to print sign-on
2) Wait for main U-Boot to print a sign-on
3) Wait for auto-boot prompt and interrupt it.

This change modifies (3) to alternatively wait for another sign-on 
prompt, which means it's doing 2 unrelated things. Better would be to 
just add a new standalone step to wait for the extra sign-on message:

1) If SPL will print a sign-on:
      Wait for SPL to print sign-on
2) Wait for main U-Boot to print a sign-on
3) If a duplicate sign-on message will be printed:
      Wait for duplicate sign-on from main U-Boot
4) Wait for auto-boot prompt and interrupt it.

Judging by the code quoted below, new step (3) above can use the value 
of bcfg.get('config_display_boardinfo_late', 'n') == 'y' to make the 
decision.

That has the advantage of not requiring the following heuristic to 
differentiate between expected sign-on messages and unexpected sign-on 
messages due to U-Boot crashing and restarting:

> +                # If CONFIG_DISPLAY_BOARDINFO_LATE is defined then we will
> +                # display the banner again after relocation. See
> +                # console_announce_r() for the implementation. The original
> +                # banner has two blank lines before it but this one has none.
> +                # We can use this to distinguish a repeat of the banner from
> +                # a reset of the board. Here we fail if we see even a single
> +                # empty line in the characters leading up to the banner.