From: Boris Brezillon <boris.brezillon@free-electrons.com>
To: Afzal Mohammed <afzal.mohd.ma@gmail.com>
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>,
Arnd Bergmann <arnd@arndb.de>,
Stephen Boyd <sboyd@codeaurora.org>,
Nicolas Ferre <nicolas.ferre@atmel.com>,
linux-kernel@vger.kernel.org,
Cyrille Pitchen <cyrille.pitchen@atmel.com>,
Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>,
linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 01/48] clk: at91: replace usleep() by udelay() calls
Date: Tue, 14 Jun 2016 18:18:20 +0200 [thread overview]
Message-ID: <20160614181820.1b817ed3@bbrezillon> (raw)
In-Reply-To: <20160614160517.GA2490@afzalpc>
On Tue, 14 Jun 2016 21:35:17 +0530
Afzal Mohammed <afzal.mohd.ma@gmail.com> wrote:
> Hi,
>
> On Mon, Jun 13, 2016 at 05:24:09PM +0200, Alexandre Belloni wrote:
> > On 11/06/2016 at 00:30:36 +0200, Arnd Bergmann wrote :
>
> > > Does this have to be called that early? It seems wasteful to always
> > > call udelay() here, when these are functions that are normally
> > > allowed to sleep.
>
> > So I've tested it and something like that would work:
> >
> > if (system_state < SYSTEM_RUNNING)
> > udelay(osc->startup_usec);
> > else
> > usleep_range(osc->startup_usec, osc->startup_usec + 1);
> >
> > But I'm afraid it would be the first driver to actually do something
> > like that (however, it is already the only driver trying to sleep).
>
> tglx has suggested to modify clock core to handle a somewhat similar
> kind of scenario (probably should work here too) and avoid driver
> changes,
>
> http://lkml.kernel.org/r/alpine.DEB.2.11.1606061448010.28031@nanos
Oh, interesting. Definitely a better solution than this custom check.
--
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
next prev parent reply other threads:[~2016-06-14 16:18 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-10 22:03 [PATCH 00/48] ARM: at91: rework Atmel TCB drivers Alexandre Belloni
2016-06-10 22:03 ` [PATCH 01/48] clk: at91: replace usleep() by udelay() calls Alexandre Belloni
2016-06-10 22:30 ` Arnd Bergmann
2016-06-10 22:37 ` Alexandre Belloni
2016-06-13 15:24 ` Alexandre Belloni
2016-06-13 19:26 ` Arnd Bergmann
2016-06-14 16:05 ` Afzal Mohammed
2016-06-14 16:18 ` Boris Brezillon [this message]
2016-06-11 7:49 ` Boris Brezillon
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