[lm-sensors] new abituguru driver in mm kernel

[j.w.r.degoede@hhs.nl (Hans de Goede)]

Sunil Kumar wrote:
> Ok, this patch seems to have made the messages go away for good (even with
> suspend/resume cycle). Because this patch helps fix it, I suspect that
> its a
> race between setting the ready state and doing a read because the while
> loop
> executes really fast and the hardware is not really that fast to respond
> when you expect it in ABIT_UGURU_STATUS_READ state in the abituguru_read
> call.
> 

Hi,

1) Thanks for all the testing and the patch
2) The while loop speed is not as fast as you think, since the while
   test condition contains a inb_p which will do 2 isa reads, thus the
   while loops speed is ISA bus bound, not CPU bound.
3) Normally I would object against the sleeping in the while since in
   the normal (no suspend problem) case, the loops are intented to
   execute pretty fast. In abituguru_update_device 38 read operations
   are done, if every read op is going to take milliseconds this will
   cause noticable stalls in sensors using applications.
4) However the 2 places where you've inserted the sleep are places where
   normally the code succeeds on the first read (so it never enters the
   while and thus never sleeps) the whole reason for the while was to
   try to fix the problem you're experiencing and you've fixed the fix,
   thanks!

So the fix is most definitly going in, thanks! Could you try the
attached version? I've also modified the suspend / resume code so that
it no longer unconditionally marks the uguru not_ready as that seemed to
make things worse, instead it now checks the uguru status and sets the
ready flag depending on the status.

Thanks,

Hans
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