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The frame counter may have got reset between disabling and enabling vblank interrupts due to DMC putting the hardware to DC5/6 states if PSR was active. The frame counter could also have stalled if PSR was active in case there was no DMC. The frame counter resetting has a user visible impact of screen freezes. Make use of drm_vblank_restore() to compute missed vblanks for the duration in which vblank interrupts were disabled and update the vblank counter with this value as diff. There's no need to check if PSR was actually active in the interrupt disabled duration, so simplify the check to a feature check. Enabling vblank interrupts wakes up the hardware from DC5/6 and prevents it from going back again as long as the there are pending interrupts. So, we don't have to explicity disallow DC5/6 after enabling vblank interrupts to keep the counter running. This change is not applicable to CHV, as enabling interrupts does not prevent the hardware from activating PSR. v2: Added comments(Rodrigo) and rewrote commit message. Cc: Ville Syrjälä <ville.syrjala@linux.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> Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20180203051302.9974-10-dhinakaran.pandiyan@intel.com
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. 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.