90ed57851e
In its early stages the VIN driver did not use an internal scratch buffer. This leads to a unnecessary complex start and stop behavior, specially for TB/BT. The driver now always allocates a scratch buffer to deal with buffer under-runs, use the scratch buffer to also simplify starting and stopping. When capture is starting use the scratch buffer instead of a user-space buffers while syncing the driver with the hardware state. This allows the driver to know that no user-space buffer is given to the hardware before the running state is reached. When capture is stopping use the scratch buffer instead of leaving the user-space buffers in place and add a check that all user-space buffers are processed by the hardware before transitioning from the stopping to stopped state. This allows the driver to know all user-space buffers given to the hardware are fully processed. This change in itself does not improve the driver much but it paves the way for future simplifications and enhancements. One direct improvement of this change is that TB/BT buffers returned to user-space while stopping will always contain both fields, that was not guaranteed before. Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org> Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.