drm/i915/display/psr: Use continuos full frame to handle frontbuffer invalidations
Instead of exit PSR when a frontbuffer invalidation happens, we can enable the PSR2 selective fetch continuous full frame, that will keep the panel updated like PSR was disabled but without keeping PSR active. So as soon as the frontbuffer flush happens we can disable the continuous full frame and start to do selective fetches much quicker than the path that would enable PSR, that will wait a few frames to actually activate PSR. Also this approach has proven to fix some glitches found in Alderlake-P when there are a lot of invalidations happening together with page flips. Some may ask why it is writing to CURSURFLIVE(), it is because that is the way that hardware team provided us to poke display to handle PSR updates, and it is being used since display 9. v2: - handling possible race conditions between frontbuffer rendering and page flips Reviewed-by: Jouni Högander <jouni.hogander@intel.com> Cc: Khaled Almahallawy <khaled.almahallawy@intel.com> Cc: Shawn C Lee <shawn.c.lee@intel.com> Cc: Jouni Högander <jouni.hogander@intel.com> Cc: Mika Kahola <mika.kahola@intel.com> Signed-off-by: José Roberto de Souza <jose.souza@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220405155344.47219-3-jose.souza@intel.com
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