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SubjectRe: [PATCH v2] i2c: core: Disable client irq on reboot/shutdown
On Fri, Jun 04, 2021 at 04:27:44PM -0700, Stephen Boyd wrote:
> From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
>
> If an i2c client receives an interrupt during reboot or shutdown it may
> be too late to service it by making an i2c transaction on the bus
> because the i2c controller has already been shutdown. This can lead to
> system hangs if the i2c controller tries to make a transfer that is
> doomed to fail because the access to the i2c pins is already shut down,
> or an iommu translation has been torn down so i2c controller register
> access doesn't work.
>
> Let's simply disable the irq if there isn't a shutdown callback for an
> i2c client when there is an irq associated with the device. This will
> make sure that irqs don't come in later than the time that we can handle
> it. We don't do this if the i2c client device already has a shutdown
> callback because presumably they're doing the right thing and quieting
> the device so irqs don't come in after the shutdown callback returns.
>
> Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> Reported-by: kernel test robot <lkp@intel.com>
> [swboyd@chromium.org: Dropped newline, added commit text, added
> interrupt.h for robot build error]
> Signed-off-by: Stephen Boyd <swboyd@chromium.org>

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

> ---
>
> Dmitry, please add Signed-off-by so this can be merged through i2c
>
> This supersedes https://lore.kernel.org/r/20210510220012.2003285-1-swboyd@chromium.org
>
> Changes from v1 (https://lore.kernel.org/r/20210604212752.3547301-1-swboyd@chromium.org)
> * Add interrupt.h include for robot
>
> drivers/i2c/i2c-core-base.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
> index 5a97e4a02fa2..e314ccaf114a 100644
> --- a/drivers/i2c/i2c-core-base.c
> +++ b/drivers/i2c/i2c-core-base.c
> @@ -24,6 +24,7 @@
> #include <linux/i2c-smbus.h>
> #include <linux/idr.h>
> #include <linux/init.h>
> +#include <linux/interrupt.h>
> #include <linux/irqflags.h>
> #include <linux/jump_label.h>
> #include <linux/kernel.h>
> @@ -627,6 +628,8 @@ static void i2c_device_shutdown(struct device *dev)
> driver = to_i2c_driver(dev->driver);
> if (driver->shutdown)
> driver->shutdown(client);
> + else if (client->irq > 0)
> + disable_irq(client->irq);
> }
>
> static void i2c_client_dev_release(struct device *dev)
>
> base-commit: 8124c8a6b35386f73523d27eacb71b5364a68c4c
> --
> https://chromeos.dev
>

--
Dmitry

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