linux-kernel - Re: [PATCH v2 1/3] net: irda: pxaficp_ir: use sched

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Message-ID: <87r3lqp83s.fsf@belgarion.home>
Date:	Tue, 22 Sep 2015 21:27:51 +0200
From:	Robert Jarzmik <robert.jarzmik@...e.fr>
To:	David Miller <davem@...emloft.net>
Cc:	samuel@...tiz.org, petr.cvek@....cz, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org, arnd@...db.de
Subject: Re: [PATCH v2 1/3] net: irda: pxaficp_ir: use sched_clock() for time management

David Miller <davem@...emloft.net> writes:

> From: Robert Jarzmik <robert.jarzmik@...e.fr>
> Date: Fri, 18 Sep 2015 18:36:56 +0200
>
>> Which brings me to wonder which is the more correct :
>>  (a) replace to reproduce the same calculation
>>      Previously mtt was compared to a difference of 76ns steps (as 307ns / 4 =
>>      76ns):
>>      while ((sched_clock() - si->last_clk) * 76 < mtt)
>> 
>>  (b) change the calculation assuming mtt is in microseconds :
>>      while ((sched_clock() - si->last_clk) * 1000 < mtt)
>> 
>> I have no IRDA protocol knowledge so unless someone points me to the correct
>> calculation I'll try my luck with (b).
>
> "a" would be "safer" and less likely to break anything, although as
> you say "b" might be more correct.
Indeed.

Well, let me try (b) then. I'll add in the commit message the timings change,
and if anybody complains a regression pops out, I'll provide a patch to fallback
to (a).

Cheers.

-- 
Robert
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