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Marek Vasut authored
In case the LCDIF is enabled in DT but unused, the clocks used by the
LCDIF are not enabled. Those clocks may even have a use count of 0 in
case there are no other users of those clocks. This can happen e.g. in
case the LCDIF drives HDMI bridge which has no panel plugged into the
HDMI connector.

Do not attempt to disable clocks in the suspend callback and re-enable
clocks in the resume callback unless the LCDIF is enabled and was in
use before the system entered suspend, otherwise the driver might end
up trying to disable clocks which are already disabled with use count
0, and would trigger a warning from clock core about this condition.

Note that the lcdif_rpm_suspend() and lcdif_rpm_resume() functions
internally perform the clocks disable and enable operations and act
as runtime PM hooks too.

Reviewed-by: default avatarLiu Ying <victor.liu@nxp.com>
Fixes: 9db35bb3 ("drm: lcdif: Add support for i.MX8MP LCDIF variant")
Signed-off-by: default avatarMarek Vasut <marex@denx.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20240226082644.32603-1-marex@denx.de
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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.