drm/radeon/kms: reorder display resume to avoid problems

On resume, we were attemping to unblank the displays before the
timing and plls had be reprogrammed which led to atom timeouts
waiting for things that are not yet programmed.  Re-program
the mode first, then reset the dpms state.

This fixes the infamous atombios timeouts on resume.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/atombios_crtc.c

@@ -253,7 +253,8 @@ void atombios_crtc_dpms(struct drm_crtc *crtc, int mode)
 	case DRM_MODE_DPMS_SUSPEND:
 	case DRM_MODE_DPMS_OFF:
 		drm_vblank_pre_modeset(dev, radeon_crtc->crtc_id);
-		atombios_blank_crtc(crtc, ATOM_ENABLE);
+		if (radeon_crtc->enabled)
+			atombios_blank_crtc(crtc, ATOM_ENABLE);
 		if (ASIC_IS_DCE3(rdev))
 			atombios_enable_crtc_memreq(crtc, ATOM_DISABLE);
 		atombios_enable_crtc(crtc, ATOM_DISABLE);

drivers/gpu/drm/radeon/radeon_device.c

@@ -910,18 +910,17 @@ int radeon_resume_kms(struct drm_device *dev)
 	radeon_pm_resume(rdev);
 	radeon_restore_bios_scratch_regs(rdev);
 
-	/* turn on display hw */
-	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
-		drm_helper_connector_dpms(connector, DRM_MODE_DPMS_ON);
-	}
-
 	radeon_fbdev_set_suspend(rdev, 0);
 	release_console_sem();
 
 	/* reset hpd state */
 	radeon_hpd_init(rdev);
 	/* blat the mode back in */
 	drm_helper_resume_force_mode(dev);
+	/* turn on display hw */
+	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+		drm_helper_connector_dpms(connector, DRM_MODE_DPMS_ON);
+	}
 	return 0;
 }