Re: [PATCH] Staging: comedi: add timeouts to while loops in s626.c
From: Ian Abbott
Date: Mon Mar 03 2014 - 09:06:32 EST
On 2014-03-01 05:48, Chase Southwood wrote:
On Friday, February 28, 2014 11:26 AM, Ian Abbott <abbotti@xxxxxxxxx> 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@xxxxxxxxx> )=-
-=( Tel: +44 (0)161 477 1898 FAX: +44 (0)161 718 3587 )=-
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/