[U-Boot] Debugging, Why USB is not stable

[Detlev Zundel]

Hi Remy,

>> Only the fact that USB is a nightmare to work with.  No, honestly, we
>> have a continuous stream of USB related problems with the current USB
>> code.
>
> This is not what I notice on the amount of fixes that are posted on the list...

Most problems go without a fix if there is an easy hardware replacement.
Even diagnosing such a problem is usually too expensive for customers.

> The only fixes I have seen the last year or two were related to newly
> added host-controller support. Apart from that it is quite silent in
> the u-boot-usb tree...
> But, anyway. I know it has some stability issues, although it is now
> much better compared to a year ago...

Yes it is and without a question I greatly appreciate your work for the
USB part.

>> As I understand it this results from the ever more diverging USB
>> implementation in U-Boot and e.g. in the Linux kernel.
>
> Indeed, It has diverged that much that I did not succeed in finding
> the real origin of the code...
>
>> Sometimes I get the impression that we would save a lot of headache by
>> starting afresh and porting the current Linux code into U-Boot thus
>> leverage all this, but nobody yet dared to start such a feat.
>
> Hey... I have dared to start it!
> (But it is a real pain to do it properly, and I stopped half way due
> to lack of time...)

I can understand that also.  My intention of the mail was to transport
my personal view of the whole area.  USB problems in my experience have
a very high cost even to diagnose, let alone fix.

Cheers
  Detlev

-- 
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