[PATCH] drm/tilcdc: restore correct display mode and contents on pm resume

[Felipe Balbi]

From: Darren Etheridge <detheridge at ti.com>

On resume the screen contents were not being restored properly.  Looking at
other DRM drivers it seems a call to drm_helper_resume_force_mode() is needed
in the resume handler to force restoration of the mode and framebuffer data.

Signed-off-by: Darren Etheridge <detheridge at ti.com>
---
 drivers/gpu/drm/tilcdc/tilcdc_drv.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/gpu/drm/tilcdc/tilcdc_drv.c b/drivers/gpu/drm/tilcdc/tilcdc_drv.c
index 171a820..1a5ddfa 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_drv.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_drv.c
@@ -563,6 +563,13 @@ static int tilcdc_pm_resume(struct device *dev)
 		if (registers[i].save && (priv->rev >= registers[i].rev))
 			tilcdc_write(ddev, registers[i].reg, priv->saved_register[n++]);
 
+	/*
+	 * if this call isn't here, the display is blank on return from
+	 * suspend.  With this call here the contents of the framebuffer
+	 * during suspend are restored correctly.
+	 */
+	drm_helper_resume_force_mode(ddev);
+
 	drm_kms_helper_poll_enable(ddev);
 
 	return 0;
-- 
1.9.0