drm/i915: Add kerneldoc for intel_pipe_update_{start, end}

	return DIV_ROUND_UP(usecs * mode->crtc_clock, 1000 * mode->crtc_htotal);

}

/**

 * intel_pipe_update_start() - start update of a set of display registers

 * @crtc: the crtc of which the registers are going to be updated

 * @start_vbl_count: vblank counter return pointer used for error checking

 *

 * Mark the start of an update to pipe registers that should be updated

 * atomically regarding vblank. If the next vblank will happens within

 * the next 100 us, this function waits until the vblank passes.

 *

 * After a successful call to this function, interrupts will be disabled

 * until a subsequent call to intel_pipe_update_end(). That is done to

 * avoid random delays. The value written to @start_vbl_count should be

 * supplied to intel_pipe_update_end() for error checking.

 *

 * Return: true if the call was successful

 */

static bool intel_pipe_update_start(struct intel_crtc *crtc, uint32_t *start_vbl_count)

{

	struct drm_device *dev = crtc->base.dev;

	return true;

}

/**

 * intel_pipe_update_end() - end update of a set of display registers

 * @crtc: the crtc of which the registers were updated

 * @start_vbl_count: start vblank counter (used for error checking)

 *

 * Mark the end of an update started with intel_pipe_update_start(). This

 * re-enables interrupts and verifies the update was actually completed

 * before a vblank using the value of @start_vbl_count.

 */

static void intel_pipe_update_end(struct intel_crtc *crtc, u32 start_vbl_count)

{

	struct drm_device *dev = crtc->base.dev;