From: Rob Purchase <rob.purchase_at_googlemail.com>
Date: Mon, 14 Jun 2010 22:22:50 +0100

On 14/06/2010 22:08, pouly amaury wrote:
>
> I have a D2 (gevaerts's one) so I could investigate. Unfortunately I
> don't know anything about the port. Could you give me some insights of
> it or tell where you think the problem could be (you talked about a
> bit-banging issue). Perhaps I would be able to figure out what is wrong.
>

I had a look at the code generated by GCC 4.4.4 and compared it to the
previous version. As I suspected, the new compiler seems to optimise
away most of the delay_loop() in i2c-telechips.c, but unfortunately the
timing of this is critical for correct I2C reads/writes. That explains
why some drivers that use the PMU chip no longer work reliably.

To fix this I need to find a way for the new compiler to generate the
same code as the old version, or simply to find a new way of writing
this loop that generates the same, working, code on both compilers.

Not necessarily a simple task :/

Rob.
Received on 2010-06-14