msm_fb: display: change implementation of updating mdp_clk and blt mode
Currently mdp clk and bw requests are predefined in a 4-entry table
passed from the board file, and the logic to decide which level to use
is mainly based on source resolution. This patch is intended to
address several issues with this approach.
One major issue is clk and bandwidth depends on seperate things, and
need to be considered seperately. e.g. with mdp composition of
multiple pipes, bw request may be high but clk requirement may still
be low. The current approach that binds these two things together
causes inefficiency of power.
Another major issue is that there is no logic to calculate mdp clk
requirement of a single pipe based upon panel clk and downscale
parameters. Further the worst case of mdp clk should be determined by
all pipe usage. Without proper logic, many underrun have been
experienced, and blt mode may not be enalbed properly.
Also mdp_clk or blt mode update must be on right timing especially
between these two pathes: overlay play and pan display. In the
situations of performance from high to low or from low to high clk and
blt must be handled properly to avoid underruns.
In a summary, to support many different panels and targets and
complicated mdp pipe usage(mdp composition), mdp driver related to clk
and bw needs to be implemented differently. This patch is to seperate
clk and bw, and maily to deal with mdp clk and blt. Later increasing
granuity of bw will be added.
Change-Id: I678fbf86d6997ed7b602ce81cf2e0fff6164d129
Signed-off-by: Siddhartha Agrawal <agrawals@codeaurora.org>
19 files changed