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authorDonggeun Yoo <donggeunyoo.kernel@gmail.com>2026-09-02 00:21:26 +0900
committerJonathan Cameron <jonathan.cameron@oss.qualcomm.com>2026-09-07 02:24:53 +0100
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tree43a2533acc955d11f5cb8be1ecba0ab8ba4cbb1e /Documentation/scsi/sd-parameters.rst
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iio: proximity: vl53l0x-i2c: claim direct mode for raw readsgrafted
vl53l0x_read_raw() starts a single-shot ranging measurement and reads back the result. Once the triggered buffer is enabled the sensor runs in continuous mode and its data-ready interrupt is routed to the trigger, so a concurrent in_distance_raw read disturbs the streaming setup and never gets its completion, returning -ETIMEDOUT. The original submission claimed direct mode here, but it was dropped during review because the driver had no buffer support at the time [1]. Continuous (buffered) mode was later added without restoring the claim [2], reintroducing the conflict. Reject direct reads while buffered capture is active by claiming direct mode around the measurement, as the vl53l1x sibling already does. Fixes: 762186c6e7b1 ("iio: proximity: vl53l0x-i2c: Added continuous mode support") Link: https://lore.kernel.org/linux-iio/20180911160300.GA9212@himanshu-Vostro-3559/ [1] Link: https://lore.kernel.org/linux-iio/20240909101508.263085-3-abhashkumarjha123@gmail.com/ [2] Signed-off-by: Donggeun Yoo <donggeunyoo.kernel@gmail.com> Cc: stable@vger.kernel.org Signed-off-by: Jonathan Cameron <jonathan.cameron@oss.qualcomm.com>
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+.. SPDX-License-Identifier: GPL-2.0
+
+======================================
+Linux SCSI Disk Driver (sd) Parameters
+======================================
+
+cache_type (RW)
+---------------
+Enable/disable drive write & read cache.
+
+=========================== === === =========== ==========
+ cache_type string WCE RCD Write cache Read cache
+=========================== === === =========== ==========
+ write through 0 0 off on
+ none 0 1 off off
+ write back 1 0 on on
+ write back, no read (daft) 1 1 on off
+=========================== === === =========== ==========
+
+To set cache type to "write back" and save this setting to the drive::
+
+ # echo "write back" > cache_type
+
+To modify the caching mode without making the change persistent, prepend
+"temporary " to the cache type string. E.g.::
+
+ # echo "temporary write back" > cache_type