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167e535438
The PLL parameters are computed by looping over the range of acceptable
M, N and E values, and selecting the combination that produces the
output frequency closest to the target. The internal frequency
constraints are taken into account by restricting the tested values for
the PLL parameters, reducing the search space. The target frequency,
however, is only taken into account when computing the post-PLL divider,
which can result in a 0 value for the divider when the PLL output
frequency being tested is lower than half of the target frequency.
Subsequent loops will produce a better set of PLL parameters, but for
some of the iterations this can result in a division by 0.
Fix it by clamping the divider value. We could instead restrict the E
values being tested in the inner loop, but that would require additional
calculation that would likely be less efficient as the E parameter can
only take three different values.
Fixes: c25c013611 ("drm: rcar-du: lvds: D3/E3 support")
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.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.