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>

1 files changed, 81 insertions, 0 deletions

diff --git a/Documentation/scsi/lpfc.rst b/Documentation/scsi/lpfc.rst
new file mode 100644
index 000000000..6e217e82b
--- /dev/null
+++ b/Documentation/scsi/lpfc.rst
@@ -0,0 +1,81 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=========================
+LPFC Driver Release Notes
+=========================
+
+
+.. important::
+
+  Starting in the 8.0.17 release, the driver began to be targeted strictly
+  toward the upstream kernel. As such, we removed #ifdefs for older kernels
+  (pre 2.6.10). The 8.0.16 release should be used if the driver is to be
+  run on one of the older kernels.
+
+  The proposed modifications to the transport layer for FC remote ports
+  and extended attribute support is now part of the upstream kernel
+  as of 2.6.12. We no longer need to provide patches for this support,
+  nor a *full* version which has old an new kernel support.
+  
+  The driver now requires a 2.6.12 (if pre-release, 2.6.12-rc1) or later
+  kernel.
+  
+  Please heed these dependencies....
+
+
+The following information is provided for additional background on the
+history of the driver as we push for upstream acceptance.
+
+Cable pull and temporary device Loss:
+
+  In older revisions of the lpfc driver, the driver internally queued i/o 
+  received from the midlayer. In the cases where a cable was pulled, link
+  jitter, or a device temporarily loses connectivity (due to its cable
+  being removed, a switch rebooting, or a device reboot), the driver could
+  hide the disappearance of the device from the midlayer. I/O's issued to
+  the LLDD would simply be queued for a short duration, allowing the device
+  to reappear or link come back alive, with no inadvertent side effects
+  to the system. If the driver did not hide these conditions, i/o would be
+  errored by the driver, the mid-layer would exhaust its retries, and the
+  device would be taken offline. Manual intervention would be required to
+  re-enable the device.
+
+  The community supporting kernel.org has driven an effort to remove
+  internal queuing from all LLDDs. The philosophy is that internal
+  queuing is unnecessary as the block layer already performs the 
+  queuing. Removing the queues from the LLDD makes a more predictable
+  and more simple LLDD.
+
+  As a potential new addition to kernel.org, the 8.x driver was asked to
+  have all internal queuing removed. Emulex complied with this request.
+  In explaining the impacts of this change, Emulex has worked with the
+  community in modifying the behavior of the SCSI midlayer so that SCSI
+  devices can be temporarily suspended while transport events (such as
+  those described) can occur.  
+
+  The proposed patch was posted to the linux-scsi mailing list. The patch
+  is contained in the 2.6.10-rc2 (and later) patch kits. As such, this
+  patch is part of the standard 2.6.10 kernel.
+
+  By default, the driver expects the patches for block/unblock interfaces
+  to be present in the kernel. No #define needs to be set to enable support.
+
+
+Kernel Support
+==============
+
+  This source package is targeted for the upstream kernel only. (See notes
+  at the top of this file). It relies on interfaces that are slowing
+  migrating into the kernel.org kernel.
+
+  At this time, the driver requires the 2.6.12 (if pre-release, 2.6.12-rc1)
+  kernel.
+
+  If a driver is needed for older kernels please utilize the 8.0.16
+  driver sources.
+
+
+Patches
+=======
+
+  Thankfully, at this time, patches are not needed.