linux-kernel - Re: [PATCH v2 04/15] spi: Replace open coded spi_controller_xfer

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Message-ID: <82a48b1c-b070-ba45-04f8-2f2bf645d893@collabora.com>
Date:   Tue, 11 Jul 2023 15:29:23 +0200
From:   AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>
To:     Mark Brown <broonie@...nel.org>
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Cristian Ciocaltea <cristian.ciocaltea@...labora.com>,
        Yang Yingliang <yangyingliang@...wei.com>,
        Amit Kumar Mahapatra via Alsa-devel 
        <alsa-devel@...a-project.org>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Tharun Kumar P <tharunkumar.pasumarthi@...rochip.com>,
        Vijaya Krishna Nivarthi <quic_vnivarth@...cinc.com>,
        Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
        linux-spi@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
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        Steven Rostedt <rostedt@...dmis.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Richard Cochran <richardcochran@...il.com>
Subject: Re: [PATCH v2 04/15] spi: Replace open coded
 spi_controller_xfer_timeout()

Il 11/07/23 15:05, Mark Brown ha scritto:
> On Tue, Jul 11, 2023 at 10:28:13AM +0200, AngeloGioacchino Del Regno wrote:
>> Il 10/07/23 17:49, Andy Shevchenko ha scritto:
> 
>>> +		ms = spi_controller_xfer_timeout(ctlr, xfer);
> 
>> I agree on using helpers, but the logic is slightly changing here: yes it is
>> unlikely (and also probably useless) to get ms == UINT_MAX, but the helper is
>> limiting the maximum timeout value to 500mS, which may not work for some slow
>> controllers/devices.
> 
> The helper is limiting the *minimum* timeout value to 500ms - it's using
> max() not min().  The idea is the other way around, that for a very fast
> transfer we don't want to end up with such a short timeout that it false
> triggers due to scheduling issues.

After reading the code again, yeah, I've totally misread it the first time. Argh!
Thanks! :-)