From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wolfram Sang <wsa@the-dreams.de>
Subject: Re: [PATCH v2] i2c: avoid sleep in IRQ context
Date: Wed, 14 Aug 2019 12:07:56 +0200
Message-ID: <20190814100756.GF1511@ninjato>
References: <20190807071807.17488-1-huangfq.daxian@gmail.com>
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In-Reply-To: <20190807071807.17488-1-huangfq.daxian@gmail.com>
Sender: linux-kernel-owner@vger.kernel.org
To: Fuqian Huang <huangfq.daxian@gmail.com>, Russell King <linux@armlinux.org.uk>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>, linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org
List-Id: linux-i2c@vger.kernel.org


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On Wed, Aug 07, 2019 at 03:18:07PM +0800, Fuqian Huang wrote:
> i2c_pxa_handler -> i2c_pxa_irq_txempty ->
> i2c_pxa_reset -> i2c_pxa_set_slave -> i2c_pxa_wait_slave
>=20
> As i2c_pxa_handler is an interrupt handler, it will finally
> calls i2c_pxa_wait_slave which calls msleep.
>=20
> Add in_interrupt check before msleep to avoid sleep
> in IRQ context.
> When in interrupt context, use mdelay instead of msleep.
>=20
> Signed-off-by: Fuqian Huang <huangfq.daxian@gmail.com>

Adding RMK to CC because he is the PXA I2C slave user I know of.

> ---
>  drivers/i2c/busses/i2c-pxa.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>=20
> diff --git a/drivers/i2c/busses/i2c-pxa.c b/drivers/i2c/busses/i2c-pxa.c
> index 2c3c3d6935c0..876e693bafd9 100644
> --- a/drivers/i2c/busses/i2c-pxa.c
> +++ b/drivers/i2c/busses/i2c-pxa.c
> @@ -456,7 +456,10 @@ static int i2c_pxa_wait_slave(struct pxa_i2c *i2c)
>  			return 1;
>  		}
> =20
> -		msleep(1);
> +		if (in_interrupt())
> +			mdelay(1);
> +		else
> +			msleep(1);
>  	}
> =20
>  	if (i2c_debug > 0)
> --=20
> 2.11.0
>=20

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