From: Mark Brown <broonie@kernel.org>
To: Jean-Michel Hautbois <jean-michel.hautbois@veo-labs.com>
Cc: linux-spi@vger.kernel.org, linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: spi-imx: wait_for_completion should timeout even in non-DMA transfer cases
Date: Tue, 22 Sep 2015 10:29:19 -0700 [thread overview]
Message-ID: <20150922172919.GK30445@sirena.org.uk> (raw)
In-Reply-To: <CAH-u=816w-uGmWt-sf2AqahRL2j7RBCah8JAKOCXFFnvVdMzhw@mail.gmail.com>
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On Mon, Sep 21, 2015 at 11:08:55AM +0200, Jean-Michel Hautbois wrote:
> 2015-09-19 19:56 GMT+02:00 Mark Brown <broonie@kernel.org>:
> > A calculated timeout is probably best.
> Well, it depends...
> If you have a 20MHz clock, then you can transfer a byte in 4µs.
> As most of the time pio_transfer is used for 8 to 32 bytes max, it
> would be irrelevant to use such a small timeout.
> I can obviously do it, but not sure if using a small (say, 100ms)
> timeout would not be better.
You want a minimum threashold, yes, but you also need to be able toc ope
with larger transfers too so need to be able to raise that where
appropriate.
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prev parent reply other threads:[~2015-09-22 17:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-18 12:38 Jean-Michel Hautbois
2015-09-19 17:56 ` Mark Brown
2015-09-21 9:08 ` Jean-Michel Hautbois
2015-09-22 17:29 ` Mark Brown [this message]
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