ENGR00211764 IPUv3 fb: 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 custom fb_set_par() method and then calls custom
fb_pan_display() method. The current implementation of ipuv3fb
reinitializes IPU display controller every time the custom
fb_set_par() method is called, which makes the display flash
if fb_set_var() is called to do panning frequently. The custom
fb_pan_display() method checks if the current xoffset and
yoffset are different from previous ones before doing actual
panning, which prevents the panning from happening within the
fb_set_var() context. This patch checks new var info to decide
whether we really need to reinitialize IPU display controller.
We ignore xoffset and yoffset update because it doesn't require
to reinitialize the controller. Users may specify activate field
of var info with FB_ACTIVATE_NOW and FB_ACTIVATE_FORCE to
reinialize the controller by force. Meanwhile, this patch removes
the check in custom fb_pan_display() method mentioned before to
have the panning work within fb_set_var() context. It doesn't
hurt to do panning again if there is no update for xoffset and
yoffset.

Signed-off-by: Liu Ying <Ying.Liu@freescale.com>

1 files changed, 30 insertions, 3 deletions

diff --git a/drivers/video/mxc/mxc_ipuv3_fb.c b/drivers/video/mxc/mxc_ipuv3_fb.c
index 4b2a19df0abb..ad21ef8f0534 100644
--- a/drivers/video/mxc/mxc_ipuv3_fb.c
+++ b/drivers/video/mxc/mxc_ipuv3_fb.c
@@ -93,6 +93,8 @@ struct mxcfb_info {
 	struct fb_info *ovfbi;
 
 	struct mxc_dispdrv_handle *dispdrv;
+
+	struct fb_var_screeninfo cur_var;
 };
 
 struct mxcfb_alloc_list {
@@ -301,6 +303,25 @@ static int _setup_disp_channel2(struct fb_info *fbi)
 	return retval;
 }
 
+static bool mxcfb_need_to_set_par(struct fb_info *fbi)
+{
+	struct mxcfb_info *mxc_fbi = fbi->par;
+
+	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.
+	 */
+	mxc_fbi->cur_var.xoffset = fbi->var.xoffset;
+	mxc_fbi->cur_var.yoffset = fbi->var.yoffset;
+
+	return !!memcmp(&mxc_fbi->cur_var, &fbi->var,
+			sizeof(struct fb_var_screeninfo));
+}
+
 /*
  * Set framebuffer parameters and change the operating mode.
  *
@@ -313,6 +334,9 @@ static int mxcfb_set_par(struct fb_info *fbi)
 	ipu_di_signal_cfg_t sig_cfg;
 	struct mxcfb_info *mxc_fbi = (struct mxcfb_info *)fbi->par;
 
+	if (!mxcfb_need_to_set_par(fbi))
+		return 0;
+
 	dev_dbg(fbi->device, "Reconfiguring framebuffer\n");
 
 	ipu_clear_irq(mxc_fbi->ipu, mxc_fbi->ipu_ch_irq);
@@ -459,6 +483,8 @@ static int mxcfb_set_par(struct fb_info *fbi)
 		}
 	}
 
+	mxc_fbi->cur_var = fbi->var;
+
 	return retval;
 }
 
@@ -879,6 +905,8 @@ static int mxcfb_ioctl(struct fb_info *fbi, unsigned int cmd, unsigned long arg)
 			} else
 				mxc_fbi->alpha_chan_en = false;
 
+			fbi->var.activate = (fbi->var.activate & ~FB_ACTIVATE_MASK) |
+						FB_ACTIVATE_NOW | FB_ACTIVATE_FORCE;
 			mxcfb_set_par(fbi);
 
 			la.alpha_phy_addr0 = mxc_fbi->alpha_phy_addr0;
@@ -1212,6 +1240,8 @@ static int mxcfb_blank(int blank, struct fb_info *info)
 		ipu_uninit_channel(mxc_fbi->ipu, mxc_fbi->ipu_ch);
 		break;
 	case FB_BLANK_UNBLANK:
+		info->var.activate = (info->var.activate & ~FB_ACTIVATE_MASK) |
+				FB_ACTIVATE_NOW | FB_ACTIVATE_FORCE;
 		ret = mxcfb_set_par(info);
 		break;
 	}
@@ -1240,9 +1270,6 @@ mxcfb_pan_display(struct fb_var_screeninfo *var, struct fb_info *info)
 	int fb_stride;
 	int i;
 
-	if (info->var.yoffset == var->yoffset)
-		return 0;	/* No change, do nothing */
-
 	/* no pan display during fb blank */
 	if (mxc_fbi->ipu_ch == MEM_FG_SYNC) {
 		struct mxcfb_info *bg_mxcfbi = NULL;