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Benjamin Gaignard 6662edcd32 media: videobuf2: Add min_reqbufs_allocation field to vb2_queue structure
Add 'min_reqbufs_allocation' field in the vb2_queue structure so drivers
can specify the minimum number of buffers to allocate when calling
VIDIOC_REQBUFS.
When initializing the queue, v4l2 core makes sure that the following
constraints are respected:
- the minimum number of buffers to allocate must be at least 2 because
one buffer is used by the hardware while the other is being processed
by userspace.
-if the driver needs 'min_queued_buffers' in the queue before calling
start_streaming(), then the minimum requirement is 'min_queued_buffers + 1'
to keep at least one buffer available for userspace.

Simplify __vb2_init_fileio() by using 'min_reqbufs_allocation' directly
to avoid duplicating the minimum number of buffers to allocate computation.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
2024-03-25 12:00:44 +01:00
Documentation A set of x86 fixes: 2024-03-24 11:13:56 -07:00
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arch EFI fixes for v6.9 #2 2024-03-24 13:54:06 -07:00
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drivers media: videobuf2: Add min_reqbufs_allocation field to vb2_queue structure 2024-03-25 12:00:44 +01:00
fs A patch to minimize blockage when processing very large batches of 2024-03-22 11:15:45 -07:00
include media: videobuf2: Add min_reqbufs_allocation field to vb2_queue structure 2024-03-25 12:00:44 +01:00
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Makefile Linux 6.9-rc1 2024-03-24 14:10:05 -07:00
README

README

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 reStructuredText 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.