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DPCD 2009h "Synchronization latency in sink" has bits that tell us the maximum number of frames sink can take to resynchronize to source timing when exiting PSR. More importantly, as per eDP 1.4b, this is the "Minimum number of frames following PSR exit that the Source device needs to wait for PSR entry." We currently use this value only to setup the number frames to wait before PSR2 selective update. But, based on the above description it makes more sense to use this to configure idle frames for both PSR1 and and PSR2. This will ensure we wait the required number of frames before activation whether it is PSR1 or PSR2. The minimum number of idle frames remains 6, while allowing sink synchronization latency and VBT to increase this value. This also solves the flip-flop between sink and source frames that I noticed on my Thinkpad X260 during PSR exit. This specific panel has a value of 8h, which according to the spec means the "Source device must wait for more than eight active frames after PSR exit before initiating PSR entry. (In this case, should be provided by the panel supplier.)" VBT however has a value of 0. Cc: Jani Nikula <jani.nikula@intel.com> Cc: Jose Roberto de Souza <jose.souza@intel.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com> Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180525033047.7596-1-dhinakaran.pandiyan@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.
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.