On Sat, Mar 14, 2015 at 1:32 PM, Wolfram Sang <wsa@xxxxxxxxxxxxx> wrote:
> On Sat, Mar 14, 2015 at 12:27:03PM +0100, Wolfram Sang wrote:
>> Hi Sebastian,
>>
>> > - i2c_transfer() has this piece:
>> > 2091 if (in_atomic() || irqs_disabled()) {
>> > 2092 ret = i2c_trylock_adapter(adap);
>> >
>> > is this irqs_disabled() is what bothers me and should not be there.
>> > pxa does a spin_lock_irq() which would enable interrupts on return /
>> > too early.
>> > mxs has a wait_for_completion() which needs irqs enabled _and_ makes
>> > in_atomic() problematic, too. I have't checked other drivers but the
>> > commit, that introduced it, does not explain why it is required.
That was some time ago, but as far as I remember, PIO in i2c_pxa was
required to enable communication with PMIC in interrupt context.
>> I haven't really looked into it, but a quick search gave me this thread
>> explaining the intention of the code in question:
>>
>> http://lists.lm-sensors.org/pipermail/i2c/2007-November/002268.html
>>
>> Regards,
>>
>> Wolfram
>>
>
> And adding a recent mail address from Mike to cc.
>
--
Sincerely yours,
Mike.
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