MLK-11536 video: mxc ipuv3 fb: Fix pan-disp frame drop issue when PRE is enabled

There could be frame drop issue when we do pan display if we update PRE next
buffer address before waiting for the flip completion, because we may hold
the flip completion already and then two continuous pan display operations may
happen quickly within one active period of frame scanning - the first PRE next
buffer address is overriden.  To fix this issue, this patch updates the buffer
address after the flip completion.

Signed-off-by: Liu Ying <Ying.Liu@freescale.com>
(cherry picked from commit d0126e42f46f6dad9ae8c6aa390b0e1bea76492e)

diff --git a/drivers/video/fbdev/mxc/mxc_ipuv3_fb.c b/drivers/video/fbdev/mxc/mxc_ipuv3_fb.c
index a72450c..d45b414 100644 (file)
--- a/drivers/video/fbdev/mxc/mxc_ipuv3_fb.c
+++ b/drivers/video/fbdev/mxc/mxc_ipuv3_fb.c
@@ -2306,6 +2306,7 @@ mxcfb_pan_display(struct fb_var_screeninfo *var, struct fb_info *info)
        u_int y_bottom;
        unsigned int fr_xoff, fr_yoff, fr_w, fr_h;
        unsigned int x_crop = 0, y_crop = 0;
+       unsigned int sec_buf_off = 0, trd_buf_off = 0;
        unsigned long base, ipu_base = 0, active_alpha_phy_addr = 0;
        bool loc_alpha_en = false;
        int fb_stride;
@@ -2393,7 +2394,6 @@ mxcfb_pan_display(struct fb_var_screeninfo *var, struct fb_info *info)
        }
 
        if (mxc_fbi->cur_prefetch) {
-               unsigned int sec_buf_off = 0, trd_buf_off = 0;
                ipu_get_channel_offset(fbi_to_pixfmt(info, true),
                                       info->var.xres,
                                       fr_h,
@@ -2405,9 +2405,6 @@ mxcfb_pan_display(struct fb_var_screeninfo *var, struct fb_info *info)
                                       &trd_buf_off);
                if (mxc_fbi->resolve)
                        sec_buf_off = mxc_fbi->gpu_sec_buf_off;
-               ipu_pre_set_fb_buffer(mxc_fbi->pre_num, base,
-                                     x_crop, y_crop,
-                                     sec_buf_off, trd_buf_off);
        } else {
                ipu_base = base;
        }
@@ -2485,6 +2482,10 @@ next:
 
                        ipu_select_buffer(mxc_fbi->ipu, mxc_fbi->ipu_ch,
                                          IPU_INPUT_BUFFER, mxc_fbi->cur_ipu_buf);
+               } else {
+                       ipu_pre_set_fb_buffer(mxc_fbi->pre_num, base,
+                                             x_crop, y_crop,
+                                             sec_buf_off, trd_buf_off);
                }
                ipu_clear_irq(mxc_fbi->ipu, mxc_fbi->ipu_ch_irq);
                ipu_enable_irq(mxc_fbi->ipu, mxc_fbi->ipu_ch_irq);