41ed08a9f6
[ Upstream commit f8fb97c915954fc6de6513cdf277103b5c6df7b3 ] RGB output doesn't allow to change parent clock rate of the display and PCLK rate is set to 0Hz in this case. The tegra_dc_commit_state() shall not set the display clock to 0Hz since this change propagates to the parent clock. The DISP clock is defined as a NODIV clock by the tegra-clk driver and all NODIV clocks use the CLK_SET_RATE_PARENT flag. This bug stayed unnoticed because by default PLLP is used as the parent clock for the display controller and PLLP silently skips the erroneous 0Hz rate changes because it always has active child clocks that don't permit rate changes. The PLLP isn't acceptable for some devices that we want to upstream (like Samsung Galaxy Tab and ASUS TF700T) due to a display panel clock rate requirements that can't be fulfilled by using PLLP and then the bug pops up in this case since parent clock is set to 0Hz, killing the display output. Don't touch DC clock if pclk=0 in order to fix the problem. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> Signed-off-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Sasha Levin <sashal@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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.