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From: Maxime Ripard <maxime.ripard@free-electrons.com>
To: Tobias Jordan <Tobias.Jordan@elektrobit.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: [RFC] spi: sun6i: disable/unprepare clocks on remove
Date: Wed, 6 Dec 2017 16:20:56 +0100	[thread overview]
Message-ID: <20171206152056.wzhoiphql322mvqw@flea.lan> (raw)
In-Reply-To: <20171206125028.fqzmy354tgf7afis@agrajag.zerfleddert.de>

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Hi Tobias,

On Wed, Dec 06, 2017 at 01:50:29PM +0100, Tobias Jordan wrote:
> sun6i_spi_probe() uses sun6i_spi_runtime_resume() to prepare/enable clocks,
> so sun6i_spi_remove() should use sun6i_spi_runtime_suspend() to
> disable/unprepare them.
> 
> Found by Linux Driver Verification project (linuxtesting.org).
> 
> Fixes: 3558fe900e8af spi: sunxi: Add Allwinner A31 SPI controller driver
> Signed-off-by: Tobias Jordan <Tobias.Jordan@elektrobit.com>
> ---
> This was found by LDV, and it looks very suspicious to me, but I'm not
> sure if the fix is that easy. Is suspend() called automatically when the
> driver is removed? If not, is it correct to unconditionally call
> suspend(), or should there be a check for the PM state instead?
> 
>  drivers/spi/spi-sun6i.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/spi/spi-sun6i.c b/drivers/spi/spi-sun6i.c
> index fb38234249a8..5e5df09e5d04 100644
> --- a/drivers/spi/spi-sun6i.c
> +++ b/drivers/spi/spi-sun6i.c
> @@ -541,6 +541,7 @@ static int sun6i_spi_probe(struct platform_device *pdev)
>  
>  static int sun6i_spi_remove(struct platform_device *pdev)
>  {
> +	sun6i_spi_runtime_suspend(&pdev->dev);

Yeah, that's not ideal. The best solution would be to call
pm_runtime_force_suspend I guess.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

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WARNING: multiple messages have this Message-ID (diff)
From: maxime.ripard@free-electrons.com (Maxime Ripard)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC] spi: sun6i: disable/unprepare clocks on remove
Date: Wed, 6 Dec 2017 16:20:56 +0100	[thread overview]
Message-ID: <20171206152056.wzhoiphql322mvqw@flea.lan> (raw)
In-Reply-To: <20171206125028.fqzmy354tgf7afis@agrajag.zerfleddert.de>

Hi Tobias,

On Wed, Dec 06, 2017 at 01:50:29PM +0100, Tobias Jordan wrote:
> sun6i_spi_probe() uses sun6i_spi_runtime_resume() to prepare/enable clocks,
> so sun6i_spi_remove() should use sun6i_spi_runtime_suspend() to
> disable/unprepare them.
> 
> Found by Linux Driver Verification project (linuxtesting.org).
> 
> Fixes: 3558fe900e8af spi: sunxi: Add Allwinner A31 SPI controller driver
> Signed-off-by: Tobias Jordan <Tobias.Jordan@elektrobit.com>
> ---
> This was found by LDV, and it looks very suspicious to me, but I'm not
> sure if the fix is that easy. Is suspend() called automatically when the
> driver is removed? If not, is it correct to unconditionally call
> suspend(), or should there be a check for the PM state instead?
> 
>  drivers/spi/spi-sun6i.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/spi/spi-sun6i.c b/drivers/spi/spi-sun6i.c
> index fb38234249a8..5e5df09e5d04 100644
> --- a/drivers/spi/spi-sun6i.c
> +++ b/drivers/spi/spi-sun6i.c
> @@ -541,6 +541,7 @@ static int sun6i_spi_probe(struct platform_device *pdev)
>  
>  static int sun6i_spi_remove(struct platform_device *pdev)
>  {
> +	sun6i_spi_runtime_suspend(&pdev->dev);

Yeah, that's not ideal. The best solution would be to call
pm_runtime_force_suspend I guess.

Maxime

-- 
Maxime Ripard, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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  reply	other threads:[~2017-12-06 15:21 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-12-06 12:50 [RFC] spi: sun6i: disable/unprepare clocks on remove Tobias Jordan
2017-12-06 12:50 ` Tobias Jordan
2017-12-06 15:20 ` Maxime Ripard [this message]
2017-12-06 15:20   ` Maxime Ripard

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