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Currently we are observing occasionally display flickering or complete freeze. This is narrowed down to be caused by single full frame update (SFF). SFF bit after it's written gets cleared by HW in subsequent vblank i.e. when the update is sent to the panel. SFF bit is required to be written together with partial frame update (PFU) bit. After the SFF bit gets cleared by the HW psr2 man trk ctl register still contains PFU bit. If there is subsequent update for any reason we will end up having selective update/fetch configuration where start line is 0 and end line is 0. Also selective fetch configuration for the planes is not properly performed. This seems to be causing problems with some panels. Using CFF without SFF doesn't work either because it may happen that psr2 man track ctl register is overwritten by next update before vblank triggers sending the update. This is causing problems to psr_invalidate/flush. Using CFF and SFF together solves the problems as SFF is cleared only by HW in subsequent vblank and the update gets sent. Fix the flickering/freeze issue by keeping CFF bit as set when PSR2 is enabled unless there is a properly configured selective update via atomic commit. v2: - Improve commit message and comments - No functional changes This is also workaround for HSD 14014971508 Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: José Roberto de Souza <jose.souza@intel.com> Cc: Mika Kahola <mika.kahola@intel.com> Reported-by: Lee Shawn C <shawn.c.lee@intel.com> Signed-off-by: Jouni Högander <jouni.hogander@intel.com> Tested-by: Lee Shawn C <shawn.c.lee@intel.com> Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20221201072308.1905679-1-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.