1 files changed, 47 insertions, 8 deletions

diff --git a/drivers/video/mx3fb.c b/drivers/video/mx3fb.c
index eec0d7b748eb..c89f8a8d36d2 100644
--- a/drivers/video/mx3fb.c
+++ b/drivers/video/mx3fb.c
@@ -269,7 +269,7 @@ struct mx3fb_info {
 	dma_cookie_t			cookie;
 	struct scatterlist		sg[2];
 
-	u32				sync;	/* preserve var->sync flags */
+	struct fb_var_screeninfo	cur_var; /* current var info */
 };
 
 static void mx3fb_dma_done(void *);
@@ -698,9 +698,29 @@ static void mx3fb_dma_done(void *arg)
 	complete(&mx3_fbi->flip_cmpl);
 }
 
+static bool mx3fb_must_set_par(struct fb_info *fbi)
+{
+	struct mx3fb_info *mx3_fbi = fbi->par;
+	struct fb_var_screeninfo old_var = mx3_fbi->cur_var;
+	struct fb_var_screeninfo new_var = fbi->var;
+
+	if ((fbi->var.activate & FB_ACTIVATE_FORCE) &&
+	    (fbi->var.activate & FB_ACTIVATE_MASK) == FB_ACTIVATE_NOW)
+		return true;
+
+	/*
+	 * Ignore xoffset and yoffset update,
+	 * because pan display handles this case.
+	 */
+	old_var.xoffset = new_var.xoffset;
+	old_var.yoffset = new_var.yoffset;
+
+	return !!memcmp(&old_var, &new_var, sizeof(struct fb_var_screeninfo));
+}
+
 static int __set_par(struct fb_info *fbi, bool lock)
 {
-	u32 mem_len;
+	u32 mem_len, cur_xoffset, cur_yoffset;
 	struct ipu_di_signal_cfg sig_cfg;
 	enum ipu_panel mode = IPU_PANEL_TFT;
 	struct mx3fb_info *mx3_fbi = fbi->par;
@@ -780,8 +800,25 @@ static int __set_par(struct fb_info *fbi, bool lock)
 	video->out_height	= fbi->var.yres;
 	video->out_stride	= fbi->var.xres_virtual;
 
-	if (mx3_fbi->blank == FB_BLANK_UNBLANK)
+	if (mx3_fbi->blank == FB_BLANK_UNBLANK) {
 		sdc_enable_channel(mx3_fbi);
+		/*
+		 * sg[0] points to fb smem_start address
+		 * and is actually active in controller.
+		 */
+		mx3_fbi->cur_var.xoffset = 0;
+		mx3_fbi->cur_var.yoffset = 0;
+	}
+
+	/*
+	 * Preserve xoffset and yoffest in case they are
+	 * inactive in controller as fb is blanked.
+	 */
+	cur_xoffset = mx3_fbi->cur_var.xoffset;
+	cur_yoffset = mx3_fbi->cur_var.yoffset;
+	mx3_fbi->cur_var = fbi->var;
+	mx3_fbi->cur_var.xoffset = cur_xoffset;
+	mx3_fbi->cur_var.yoffset = cur_yoffset;
 
 	return 0;
 }
@@ -802,7 +839,7 @@ static int mx3fb_set_par(struct fb_info *fbi)
 
 	mutex_lock(&mx3_fbi->mutex);
 
-	ret = __set_par(fbi, true);
+	ret = mx3fb_must_set_par(fbi) ? __set_par(fbi, true) : 0;
 
 	mutex_unlock(&mx3_fbi->mutex);
 
@@ -901,8 +938,8 @@ static int mx3fb_check_var(struct fb_var_screeninfo *var, struct fb_info *fbi)
 	var->grayscale = 0;
 
 	/* Preserve sync flags */
-	var->sync |= mx3_fbi->sync;
-	mx3_fbi->sync |= var->sync;
+	var->sync |= mx3_fbi->cur_var.sync;
+	mx3_fbi->cur_var.sync |= var->sync;
 
 	return 0;
 }
@@ -1043,8 +1080,8 @@ static int mx3fb_pan_display(struct fb_var_screeninfo *var,
 		return -EINVAL;
 	}
 
-	if (fbi->var.xoffset == var->xoffset &&
-	    fbi->var.yoffset == var->yoffset)
+	if (mx3_fbi->cur_var.xoffset == var->xoffset &&
+	    mx3_fbi->cur_var.yoffset == var->yoffset)
 		return 0;	/* No change, do nothing */
 
 	y_bottom = var->yoffset;
@@ -1127,6 +1164,8 @@ static int mx3fb_pan_display(struct fb_var_screeninfo *var,
 	else
 		fbi->var.vmode &= ~FB_VMODE_YWRAP;
 
+	mx3_fbi->cur_var = fbi->var;
+
 	mutex_unlock(&mx3_fbi->mutex);
 
 	dev_dbg(fbi->device, "Update complete\n");