f3e9632cb6
drm_format_horz_chroma_subsampling and drm_format_vert_chroma_subsampling are basically a lookup in the drm_format_info table plus an access to the hsub and vsub fields of the appropriate entry. Most drivers are using this function while having access to the entry already, which means that we will perform an unnecessary lookup. Removing the call to these functions is therefore more efficient. Some drivers will not have access to that entry in the function, but in this case the overhead is minimal (we just have to call drm_format_info() to perform the lookup) and we can even avoid multiple, inefficient lookups in some places that need multiple fields from the drm_format_info structure. This is amplified by the fact that most of the time the callers will have to retrieve both the vsub and hsub fields, meaning that they would perform twice the lookup. Reviewed-by: Emil Velikov <emil.velikov@collabora.com> Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com> Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com> Link: https://patchwork.freedesktop.org/patch/msgid/6b3cceb8161e2c1d40c2681de99202328b0a8abc.1558002671.git-series.maxime.ripard@bootlin.com
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.