[U-Boot] [PATCH 1/5] Add bmp_layout module for accessing BMP header data

[Igor Grinberg]

On 02/05/13 15:20, Wolfgang Denk wrote:
> Dear Igor,
> 
> In message <5110EF4F.3080308 at compulab.co.il> you wrote:
>>
>>> Why should we?  Who tells that this is not perfectly legal on the
>>> running system?
>>
>> It might be perfectly legal, but we also consider a tons of work
>> explaining why and how this should be done (needless to mention the
>> amount of bricked boards).
> 
> Please understand that I will not really buy this "bricked bord"
> argument.  This is an issue where system builders and users are
> involved.  Apparently the system builders agree that performance
> is so important that they compile with optimizer options that do
> not tolerate unaligned accesses, thus introducing the problem.
> This is OK for systems where only educated users have access.  If you
> open the U-Boot console interface to uneducated users, you are always
> running some risk that a stupid command will brick the board or at
> least make it no longer usable to that user.  And as a user you should
> well be aware that bad things can happen, and that it is an excellent
> idea to actually test any new settings or operations before installing
> these.  If users ignore even such basic rules, then the situation is
> f*cked up and cannot be helped - if it's not the spalsh screen, then
> these users will find other ways to run into trouble.

Totally... I agree the bricked bored ;-) should not be an argument,
but the tons of work might be...

> 
>>> Let me repeat it: U-Boot is a boot loader.  It is not intended for
>>> meddling by avarage Johnny Loser, but for system programmers who know
>>> what they are doing. And anyone doing such things is well adviced to
>>> _test_ his settings on the command line before storing these for
>>> automatic use.  As I mentioned before, omitting such tests is a sin
>>> that carries with it its own punishment.
>>
>> What are you trying to say?
>> Is it that the environment variables change and in particular
>> the splash screen installation _must_ be done by a programmer?
> 
> I tried to be clear: people who work on such a level are supposed to
> know what they are doing.
> 
> 
> I find it interesting that a lot of arguments get raised here how
> important this issue is (is it? who has actually bricked a system
> this way?),

This is a relatively new default setting for the compiler,
and I think this is the reason why you (still) haven't heard
about it.
Also, do you really expect that whoever gets the board bricked
will go complaining to the mailing list?
I know many users, that don't even know about the mailing list
existence at all and they don't care...
What they do care is for the feature to work and have a simple
yet usable user API.

> and how that is a special case (here I disagree), but
> so far you all appear to ignore my argument of testing settings
> before putting these to use.

Loading of the splash screen has been a part of the U-Boot boot
sequence for ages, so the test of the feature is roughly just place
the bmp image in the right place on the storage device, set the
splashimage variable and reset the board.
They don't think about the new compiler right away and they don't
think about the bmp header. All they think about is: "I always did
it like this, so lets do it the same way...", and here comes the
new compiler default...

Now, I agree with you, that the above might be not the best way.
And I agree that U-Boot, as a boot loader, should be just a dumb
piece of code that does whatever the user/programmer tells it to do.

Is there any argument, from what was said in this (and other) thread,
you agree with?
Can you propose a feasible (yet not too expensive and not out of
mainline tree) solution?

-- 
Regards,
Igor.