drm/kms/radeon: Add support for precise vblank timestamping.
This patch adds new functions for use by the drm core: .get_vblank_timestamp() provides a precise timestamp for the end of the most recent (or current) vblank interval of a given crtc, as needed for the DRI2 implementation of the OML_sync_control extension. It is a thin wrapper around the drm function drm_calc_vbltimestamp_from_scanoutpos() which does almost all the work and is shared across drivers. .get_scanout_position() provides the current horizontal and vertical video scanout position and "in vblank" status of a given crtc, as needed by the drm for use by drm_calc_vbltimestamp_from_scanoutpos(). The function is also used by the dynamic gpu reclocking code to determine when it is safe to reclock inside vblank. For that purpose radeon_pm_in_vbl() is modified to accomodate a small change in the function prototype of the radeon_get_crtc_scanoutpos() which is hooked up to .get_scanout_position(). This code has been tested on AVIVO hardware, a RV530 (ATI Mobility Radeon X1600) in a Intel Core-2 Duo MacBookPro and some R600 variant (FireGL V7600) in a single cpu AMD Athlon 64 PC. Signed-off-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de> Reviewed-by: Alex Deucher <alexdeucher@gmail.com> Signed-off-by: Dave Airlie <airlied@redhat.com>
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