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From: Maxime Ripard <maxime.ripard@bootlin.com>
To: Sergey Suloev <ssuloev@orpaltech.com>
Cc: Mark Brown <broonie@kernel.org>, Chen-Yu Tsai <wens@csie.org>,
	linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/6] spi: core: handle timeout error from transfer_one()
Date: Wed, 4 Apr 2018 09:08:18 +0200	[thread overview]
Message-ID: <20180404070817.6cens44jvlmdaxtm@flea> (raw)
In-Reply-To: <dad0ea81-2dd6-ccc3-a0c9-cf20ff195b7f@orpaltech.com>

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On Tue, Apr 03, 2018 at 07:24:11PM +0300, Sergey Suloev wrote:
> On 04/03/2018 07:18 PM, Mark Brown wrote:
> > On Tue, Apr 03, 2018 at 07:00:55PM +0300, Sergey Suloev wrote:
> > > On 04/03/2018 06:52 PM, Mark Brown wrote:
> > > > On Tue, Apr 03, 2018 at 06:29:00PM +0300, Sergey Suloev wrote:
> > > > > As long as sun4i/sun6i SPI drivers have overriden the default
> > > > > "wait for completion" procedure then we need to properly
> > > > > handle -ETIMEDOUT error from transfer_one().
> > > > Why is this connected to those drivers specifically?
> > > These 2 drivers have their own "waiting" code and not using the code from
> > > SPI core.
> > Does this not apply to any other driver - why is this something we only
> > have to do when these drivers do it?  That's what's setting off alarm
> > bells.
> 
> sun4i/sun6i drivers have let's say "smart" waiting while SPI core uses a
> fixed interval to wait.
> 
> I can't say for every SPI driver in kernel, that's outside of my area of
> expertise.

I'm not sure what's specific about the sun4i / sun6i case here. Your
patch doesn't have anything to do with the delay before the timeout,
but the fact that we return -ETIMEDOUT in the first place.

And I'm pretty sure that papering over an error returned by a driver
is not the right thing to do.

Maxime

-- 
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com

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WARNING: multiple messages have this Message-ID (diff)
From: maxime.ripard@bootlin.com (Maxime Ripard)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 1/6] spi: core: handle timeout error from transfer_one()
Date: Wed, 4 Apr 2018 09:08:18 +0200	[thread overview]
Message-ID: <20180404070817.6cens44jvlmdaxtm@flea> (raw)
In-Reply-To: <dad0ea81-2dd6-ccc3-a0c9-cf20ff195b7f@orpaltech.com>

On Tue, Apr 03, 2018 at 07:24:11PM +0300, Sergey Suloev wrote:
> On 04/03/2018 07:18 PM, Mark Brown wrote:
> > On Tue, Apr 03, 2018 at 07:00:55PM +0300, Sergey Suloev wrote:
> > > On 04/03/2018 06:52 PM, Mark Brown wrote:
> > > > On Tue, Apr 03, 2018 at 06:29:00PM +0300, Sergey Suloev wrote:
> > > > > As long as sun4i/sun6i SPI drivers have overriden the default
> > > > > "wait for completion" procedure then we need to properly
> > > > > handle -ETIMEDOUT error from transfer_one().
> > > > Why is this connected to those drivers specifically?
> > > These 2 drivers have their own "waiting" code and not using the code from
> > > SPI core.
> > Does this not apply to any other driver - why is this something we only
> > have to do when these drivers do it?  That's what's setting off alarm
> > bells.
> 
> sun4i/sun6i drivers have let's say "smart" waiting while SPI core uses a
> fixed interval to wait.
> 
> I can't say for every SPI driver in kernel, that's outside of my area of
> expertise.

I'm not sure what's specific about the sun4i / sun6i case here. Your
patch doesn't have anything to do with the delay before the timeout,
but the fact that we return -ETIMEDOUT in the first place.

And I'm pretty sure that papering over an error returned by a driver
is not the right thing to do.

Maxime

-- 
Maxime Ripard, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com
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  reply	other threads:[~2018-04-04  7:08 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-03 15:28 [PATCH v2 0/6] spi: Add support for DMA transfers in sun4i SPI driver Sergey Suloev
2018-04-03 15:28 ` Sergey Suloev
2018-04-03 15:29 ` [PATCH v2 1/6] spi: core: handle timeout error from transfer_one() Sergey Suloev
2018-04-03 15:29   ` Sergey Suloev
2018-04-03 15:52   ` Mark Brown
2018-04-03 15:52     ` Mark Brown
2018-04-03 16:00     ` Sergey Suloev
2018-04-03 16:00       ` Sergey Suloev
2018-04-03 16:18       ` Mark Brown
2018-04-03 16:18         ` Mark Brown
2018-04-03 16:24         ` Sergey Suloev
2018-04-03 16:24           ` Sergey Suloev
2018-04-04  7:08           ` Maxime Ripard [this message]
2018-04-04  7:08             ` Maxime Ripard
2018-04-04 10:42             ` Mark Brown
2018-04-04 10:42               ` Mark Brown
2018-04-04 19:19             ` Sergey Suloev
2018-04-04 19:19               ` Sergey Suloev
2018-04-03 15:29 ` [PATCH v2 2/6] spi: sun4i: restrict transfer length in PIO-mode Sergey Suloev
2018-04-03 15:29   ` Sergey Suloev
2018-04-04  7:10   ` Maxime Ripard
2018-04-04  7:10     ` Maxime Ripard
2018-04-03 15:29 ` [PATCH v2 3/6] spi: sun4i: coding style/readability improvements Sergey Suloev
2018-04-03 15:29   ` Sergey Suloev
2018-04-04  7:13   ` Maxime Ripard
2018-04-04  7:13     ` Maxime Ripard
2018-04-03 15:29 ` [PATCH v2 4/6] spi: sun4i: use completion provided by SPI core driver Sergey Suloev
2018-04-03 15:29   ` Sergey Suloev
2018-04-04  7:13   ` Maxime Ripard
2018-04-04  7:13     ` Maxime Ripard
2018-04-03 15:29 ` [PATCH v2 5/6] spi: sun4i: introduce register set/unset helpers Sergey Suloev
2018-04-03 15:29   ` Sergey Suloev
2018-04-03 15:29   ` Sergey Suloev
2018-04-04  7:14   ` Maxime Ripard
2018-04-04  7:14     ` Maxime Ripard
2018-04-03 15:29 ` [PATCH v2 6/6] spi: sun4i: add DMA transfers support Sergey Suloev
2018-04-03 15:29   ` Sergey Suloev

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