[U-Boot-Users] u-boot kernel parameters

[S. Egbert <s.egbert@sbcglobal.net>]

> 
>> 4.  Make heavy use of on-board LED indicators by calling ioremap() and
>> poking your virtualized hardware register location to flip on the LED
>> indicators.
> 
> I strongly recommend *against* doing this, at least unless  you  know
> *exactly*  what  you  are doing (and then you don't need this because
> you will use a BDI2000 anyway). I've seen to many reports  of  "Linux
> crashes  when  enabling  the  MMU"  that  were  cause by exactly such
> attempts.
> 

Oh yeah... I totally agreed on your recommendation.  But when one is
located FAR FAR AWAY from the cushy software laboratory and without a
hardware debugger, I have find this technique extremely useful in very
DARK, DARK circumstances.

Another time, I had to bring-up a custom board that is totally devoid of
inputs/output interface (as those interfaces were still under HW
development), this LED method saved my bacon as I SLOWLY and PAINFULLY
integrate Xilinx UARTLITE driver (if one is extremely careful about
setting aside a TLB region JUST for that purpose.

Alright, alright.... Let us call this LED indicators, a 'poor man's'
debugger.  Desperate acts calls for desperate measure.