From: Alexandre Belloni <alexandre.belloni@free-electrons.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arm-kernel@lists.infradead.org,
Nicolas Ferre <nicolas.ferre@atmel.com>,
Boris Brezillon <boris.brezillon@free-electrons.com>,
Stephen Boyd <sboyd@codeaurora.org>,
linux-kernel@vger.kernel.org,
Cyrille Pitchen <cyrille.pitchen@atmel.com>,
Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>,
linux-clk@vger.kernel.org
Subject: Re: [PATCH 01/48] clk: at91: replace usleep() by udelay() calls
Date: Mon, 13 Jun 2016 17:24:09 +0200 [thread overview]
Message-ID: <20160613152409.GD3240@piout.net> (raw)
In-Reply-To: <11395561.bQatt85IOg@wuerfel>
On 11/06/2016 at 00:30:36 +0200, Arnd Bergmann wrote :
> On Saturday, June 11, 2016 12:03:04 AM CEST Alexandre Belloni wrote:
> > From: Cyrille Pitchen <cyrille.pitchen@atmel.com>
> >
> > Fix the main and slow clock .prepare() implementations which used to call
> > usleep() when the scheduler wasn't ready yet.
> >
>
> 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).
--
Alexandre Belloni, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
next prev parent reply other threads:[~2016-06-13 15:24 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 [this message]
2016-06-13 19:26 ` Arnd Bergmann
2016-06-14 16:05 ` Afzal Mohammed
2016-06-14 16:18 ` Boris Brezillon
2016-06-11 7:49 ` Boris Brezillon
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