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    Subject[PATCH AUTOSEL 5.4 62/63] i2c: core: Disable client irq on reboot/shutdown
    Date
    From: Dmitry Torokhov <dmitry.torokhov@gmail.com>

    [ Upstream commit b64210f2f7c11c757432ba3701d88241b2b98fb1 ]

    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.

    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>
    Signed-off-by: Wolfram Sang <wsa@kernel.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    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 840f59650c7c..1b93fae58ec7 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>
    @@ -459,6 +460,8 @@ 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)
    --
    2.30.2
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