drm/radeon: Switch to drm_vblank_on/off

These should be functionally equivalent to the older per/post modeset
functions, except that they block out drm_vblank_get right away.
There's only the clock adjusting code (outside of pageflips) in
readone which uses drm_vblank_get. But that code doesn't synchronize
against concurrent modesets and instead handles any such races by
waiting for the right vblank to arrive with a short timetout.

The longer-term plan here is to switch all kms drivers to
drm_vblank_on/off so that common code like pending event cleanup can
be done there, while drm_vblank_pre/post_modeset will be purely
drm internal for the old UMS ioctl.

Note that with this patch Michel uncovered a bug in the dri3
implementation of the DDX (it does vblank waits when the pipe is off),
which had to be fixed first.

Cc: Michel Dänzer <michel.daenzer@amd.com>
Acked-and-tested-by: Michel Dänzer <michel.daenzer@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/atombios_crtc.c

@@ -275,13 +275,13 @@ void atombios_crtc_dpms(struct drm_crtc *crtc, int mode)
 		if (ASIC_IS_DCE3(rdev) && !ASIC_IS_DCE6(rdev))
 			atombios_enable_crtc_memreq(crtc, ATOM_ENABLE);
 		atombios_blank_crtc(crtc, ATOM_DISABLE);
-		drm_vblank_post_modeset(dev, radeon_crtc->crtc_id);
+		drm_vblank_on(dev, radeon_crtc->crtc_id);
 		radeon_crtc_load_lut(crtc);
 		break;
 	case DRM_MODE_DPMS_STANDBY:
 	case DRM_MODE_DPMS_SUSPEND:
 	case DRM_MODE_DPMS_OFF:
-		drm_vblank_pre_modeset(dev, radeon_crtc->crtc_id);
+		drm_vblank_off(dev, radeon_crtc->crtc_id);
 		if (radeon_crtc->enabled)
 			atombios_blank_crtc(crtc, ATOM_ENABLE);
 		if (ASIC_IS_DCE3(rdev) && !ASIC_IS_DCE6(rdev))

drivers/gpu/drm/radeon/radeon_legacy_crtc.c

@@ -331,13 +331,13 @@ static void radeon_crtc_dpms(struct drm_crtc *crtc, int mode)
 									 RADEON_CRTC_DISP_REQ_EN_B));
 			WREG32_P(RADEON_CRTC_EXT_CNTL, crtc_ext_cntl, ~(mask | crtc_ext_cntl));
 		}
-		drm_vblank_post_modeset(dev, radeon_crtc->crtc_id);
+		drm_vblank_on(dev, radeon_crtc->crtc_id);
 		radeon_crtc_load_lut(crtc);
 		break;
 	case DRM_MODE_DPMS_STANDBY:
 	case DRM_MODE_DPMS_SUSPEND:
 	case DRM_MODE_DPMS_OFF:
-		drm_vblank_pre_modeset(dev, radeon_crtc->crtc_id);
+		drm_vblank_off(dev, radeon_crtc->crtc_id);
 		if (radeon_crtc->crtc_id)
 			WREG32_P(RADEON_CRTC2_GEN_CNTL, mask, ~(RADEON_CRTC2_EN | mask));
 		else {