5197c49d20
PC8+ clobbers a bunch of displays registers which need to
be restored by hand or else we lost a bunch of workarounds.
The important ones for us are at least CHICKEN_PAR2* and
CHICKEN_PIPESL*.
Curiously at least some CHICKEN_PAR1* registers
are preserved by the hardware/firmware. Unfortunately Bspec
doens't really specify what gets clobbered vs. preserved
so further reverse engieering might be warranted to figure
out the specifics.
Note that PCH_LP_PARTITION_LEVEL_DISABLE is also set by
lpt_init_clock_gating() so the rmw in hsw_disable_pc8()
is now redundant. Remove it.
TODO: I suspect most gt stuff doesn't need this and we should
finish moving all of them from init_clock_gating() to
a more appropriate place...
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230609141404.12729-2-ville.syrjala@linux.intel.com
Reviewed-by: Jouni Högander <jouni.hogander@intel.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.