mx3fb: support pan display with fb_set_var

Users may call FBIOPUT_VSCREENINFO ioctrl to do pan display.
This ioctrl relies on fb_set_var() to do the job. fb_set_var()
calls the custom fb_set_par() method and then calls the custom
fb_pan_display() method. Before calling the custom fb_pan_display()
method, info->var is already updated from the new *var in fb_set_var().
And, the custom fb_pan_display() method checks if xoffset and yoffset
in info->var and the new *var are different before doing actual panning,
which prevents the panning from happening within fb_set_var() context.
This patch caches the current var info locally in mx3fb driver so that
pan display with fb_set_var is supported.

Signed-off-by: Liu Ying <Ying.Liu@freescale.com>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>

diff --git a/drivers/video/mx3fb.c b/drivers/video/mx3fb.c
index eec0d7b748eb9e503ea8a9ffa0d007b3a91ed0c5..da1d052a18a591ef2439368e1a22ac39c5e440ac 100644 (file)
--- 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 *);
@@ -700,7 +700,7 @@ static void mx3fb_dma_done(void *arg)
 
 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 +780,25 @@ 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;
 }
@@ -901,8 +918,8 @@ 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 +1060,8 @@ 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 +1144,8 @@ 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");