It does seem that this is a timing issue. However adding various
usleep() around jtag.c and arm11_dbtap.c file does not produce errors on
r1817. Also increasing TAP_IDLE's does not break the code.

It might be more productive to capture some of the data going to ft2232
interface. Is there a simple way to add LOG_INFO()'s to show what is
being send out onto USB cable (in terms of commands or actual bits)? I
can add some timing info as well and compare r1817 & r1822 output
versions.

Since all the data is written to memory and it is always correct, then
all arm11 commands (32-bit memory writes) are executed correctly. So,
the only issue is really with address incrementing. Which part of the
code causes the memory pointer to increment? Perhaps I can look at that
code. 

--Michal


On Sun, 2009-09-13 at 09:34 +0200, Øyvind Harboe wrote:
> > So r1817 passed but r1822 does not. r1817-r1821 do not compile.
> >
> > There are a lot of changes to jtag.c file here between r1817 - r1822.
> > Anybody?
> 
> I've diffed 1817 and 1822 and I find nothing that could explain
> arm11 burst writes failing.  It's quite puzzling.
> 
> The only difference I could find by reading the code is
> timing changes, i.e. it happens to break between 1817 and
> 1822 on your machine + interface, but it would break
> somewhere else on another setup. If this is the case, then
> the code was *always* broken(i.e. not robust), it just
> happened to work.
> 
> The other hint that you have found is that removing TAP_IDLE's
> will make the code work, i.e. the faster the code is, the better
> chance it is of it running. If *timing* is the only difference
> when removing/adding TAP_IDLE's, then this is another hint
> at a race condition.
> 
> These next steps come to mind:
> 
> 1. Verify assumptions. Are you *sure* 1817 work and 1822 fails?
> 
> 2. Try to break 1822. Try adding usleep() delays around the
> code, e.g. to  jtag_execute_queue().
> 
> 
> 
> 

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