Messages in this thread | | | Date | Mon, 3 Mar 2014 14:05:30 +0000 | From | Ian Abbott <> | Subject | Re: [PATCH] Staging: comedi: add timeouts to while loops in s626.c |
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On 2014-03-01 05:48, Chase Southwood wrote: > On Friday, February 28, 2014 11:26 AM, Ian Abbott <abbotti@mev.co.uk> wrote: >> On 2014-02-28 07:35, Chase Southwood wrote: >>> And finally, are timeouts here even necessary or helpful, or are there >>> any better ways to do it? >> >> In the case of s626_send_dac(), it doesn't seem to be used in any >> critical sections, so it could make use of Hartley's comedi_timeout(). >> >> Some of the timeout errors could be propagated, especially for >> s626_send_dac() which is only reachable from very few paths. >> > > Awesome, I'll swap all of my timeouts out for comedi_timeout() in s626_send_dac(). > As for propagating the timeout errors, could you please clarify that a bit further? Both of the functions > which I add timeouts inside of in this patch return void, and so in their current state they cannot return any error > values. Would you like them (or at least s626_send_dac()) to instead return an error upon timeout/or success on success, > or am I just totally misunderstanding your meaning of propagate here?
s626_send_dac() could be changed to return an int value 0 on success or -ETIMEDOUT on timeout. s626_set_dac() and s626_write_trim_dac() could be changed to return an int - just return the result of s626_send_dac(). Similarly, the result of those functions could be either propagated upwards. This could all be done in a separate patch (or patches).
>> There are other infinite loops involving calls to the s626_mc_test() >> function, but those could be dealt with by other patches. > > Yeah, I saw those...I'll whip up a patch for them, just wanted to verify that everything looks pretty good here > before I started on that. I'll have that right out!
Yes, anything is an improvement on an infinite loop waiting for the hardware to do something!
-- -=( Ian Abbott @ MEV Ltd. E-mail: <abbotti@mev.co.uk> )=- -=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=-
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