forked from Minki/linux
1cfe19aa61
DRM page flip vblank events requested by page flips or atomic commits are created by the DRM core and then passed to driver through CRTC states (for atomic commit) or directly to the page flip handler (for legacy page flips). The events are then kept aside until the page flip completes, at which point drivers queue them for delivery with a call to drm_send_vblank_event(). When a DRM file handle is closed events pending for delivery are cleaned up automatically by the DRM core. Events that have been passed to the driver but haven't completed yet, however, are not handled by the DRM core. Drivers are responsible for destroying them and must not attempt to queue them for delivery. This is usually handled by drivers' preclose() handlers that cancel and destroy page flip events that reference the file handle being closed. With asynchronous atomic updates the story becomes more complex. Several asynchronous atomic updates can be pending, each of them carrying per-CRTC events. As the atomic_commit() operation doesn't receive a file handle context, drivers can't know which file handle a pending update refers to, making it difficult to cancel or wait for completion of updates related to the file handle being closed. It should be noted that cancelling page flips or waiting for atomic updates completion isn't required by the DRM core when closing a file handle. The only requirement is that no event gets queued for delivery after the preclose() operation returns. This can easily be achieved by storing events for atomic commits in a list, unlinking events from the file handle being closed by setting the file_priv field to NULL, and skipping delivery of unlinked events. This logic replaces the page flip cancellation completely. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com> |
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| Makefile | ||