Dear Andreas,
In message 516D62E1.7090306@gmail.com you wrote:
But how about other places in u-boot hang()ing the device? How can we tell the user that state without a terminal? If one plugs a uart cable he might see some cause of the hang() but this is not acceptable for some groups of users. Is it wise to completely stop a device without showing the state to the user?
If you want to tell the user, this should be done _before_ calling hang() - if you decide to hang() your board. Keep in mind that you don't have to define CONFIG_PANIC_HANG.
Also, as done in arch/powerpc/lib/board.c we usually print an error message on the console device, and we can call bootstage_error(), which could initialte such actions.
This question is a bit hypothetical cause we should eliminate the root causes for hang()s before going to market. However I would like to hear your thoughts about that.
You cannot eliminate all causes that will lead a board to run into hang(). There may be simply broken hardware, for example...
Best regards,
Wolfgang Denk