Re: FAILED: patch "[PATCH] iio: imu: st_lsm6dsx: Fix selection of ST_LSM6DS3_ID" failed to apply to 4.19-stable tree

[Sasha Levin <sashal@kernel.org>]

On Sun, Jan 19, 2020 at 02:33:30PM +0100, gregkh@linuxfoundation.org wrote:
>
>The patch below does not apply to the 4.19-stable tree.
>If someone wants it applied there, or to any other stable or longterm
>tree, then please email the backport, including the original git commit
>id to <stable@vger.kernel.org>.
>
>thanks,
>
>greg k-h
>
>------------------ original commit in Linus's tree ------------------
>
>From fb4fbc8904e786537e29329d791147389e1465a2 Mon Sep 17 00:00:00 2001
>From: Stephan Gerhold <stephan@gerhold.net>
>Date: Mon, 16 Dec 2019 13:41:20 +0100
>Subject: [PATCH] iio: imu: st_lsm6dsx: Fix selection of ST_LSM6DS3_ID
>
>At the moment, attempting to probe a device with ST_LSM6DS3_ID
>(e.g. using the st,lsm6ds3 compatible) fails with:
>
>    st_lsm6dsx_i2c 1-006b: unsupported whoami [69]
>
>... even though 0x69 is the whoami listed for ST_LSM6DS3_ID.
>
>This happens because st_lsm6dsx_check_whoami() also attempts
>to match unspecified (zero-initialized) entries in the "id" array.
>ST_LSM6DS3_ID = 0 will therefore match any entry in
>st_lsm6dsx_sensor_settings (here: the first), because none of them
>actually have all 12 entries listed in the "id" array.
>
>Avoid this by additionally checking if "name" is set,
>which is only set for valid entries in the "id" array.
>
>Note: Although the problem was introduced earlier it did not surface until
>commit 52f4b1f19679 ("iio: imu: st_lsm6dsx: add support for accel/gyro unit of lsm9ds1")
>because ST_LSM6DS3_ID was the first entry in st_lsm6dsx_sensor_settings.
>
>Fixes: d068e4a0f921 ("iio: imu: st_lsm6dsx: add support to multiple devices with the same settings")
>Cc: <stable@vger.kernel.org> # 5.4
>Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
>Signed-off-by: Stephan Gerhold <stephan@gerhold.net>
>Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

I don't think that this is needed on anything older than 5.4 because
they don't have 801a6e0af0c6 ("iio: imu: st_lsm6dsx: add support to
LSM6DSO"), the fixes tag might be misleading here a bit.

-- 
Thanks,
Sasha