DSS2: Prefer 3-tap filter

The 5-tap filter seems rather unstable. With some scaling settings it
works and with some it doesn't even though the functional clock remains
within the TRM limits. So prefer the 3-tap filter unless the functional
clock required for it is too high.

Signed-off-by: Ville Syrjälä <ville.syrjala@nokia.com>

diff --git a/drivers/video/omap2/dss/dispc.c b/drivers/video/omap2/dss/dispc.c
index b8a3329..b631dd8 100644 (file)
--- a/drivers/video/omap2/dss/dispc.c
+++ b/drivers/video/omap2/dss/dispc.c
@@ -1405,15 +1405,10 @@ static unsigned long calc_fclk_five_taps(u16 width, u16 height,
 }
 
 static unsigned long calc_fclk(u16 width, u16 height,
 }
 
 static unsigned long calc_fclk(u16 width, u16 height,

-               u16 out_width, u16 out_height,
-               enum omap_color_mode color_mode, bool five_taps)
+               u16 out_width, u16 out_height)

 {
        unsigned int hf, vf;
 
 {
        unsigned int hf, vf;
 

-       if (five_taps)
-               return calc_fclk_five_taps(width, height,
-                               out_width, out_height, color_mode);
-

        /*
         * FIXME how to determine the 'A' factor
         * for the no downscaling case ?
        /*
         * FIXME how to determine the 'A' factor
         * for the no downscaling case ?


@@ -1494,7 +1489,7 @@ static int _dispc_setup_plane(enum omap_plane plane,
        } else {
                /* video plane */
 
        } else {
                /* video plane */
 

-               unsigned long fclk;
+               unsigned long fclk = 0;

 
                if (out_width < width / maxdownscale ||
                   out_width > width * 8)
 
                if (out_width < width / maxdownscale ||
                   out_width > width * 8)


@@ -1530,20 +1525,22 @@ static int _dispc_setup_plane(enum omap_plane plane,
                /* Must use 5-tap filter? */
                five_taps = height > out_height * 2;
 
                /* Must use 5-tap filter? */
                five_taps = height > out_height * 2;
 

-               /* Try to use 5-tap filter whenever possible. */
-               if (cpu_is_omap34xx() && !five_taps &&
-                   height > out_height && width <= 1024) {
-                       fclk = calc_fclk_five_taps(width, height,
-                                       out_width, out_height, color_mode);
-                       if (fclk <= dispc_fclk_rate())
+               if (!five_taps) {
+                       fclk = calc_fclk(width, height,
+                                       out_width, out_height);
+
+                       /* Try 5-tap filter if 3-tap fclk is too high */
+                       if (cpu_is_omap34xx() && height > out_height &&
+                                       fclk > dispc_fclk_rate())

                                five_taps = true;
                }
 
                if (width > (2048 >> five_taps))
                        return -EINVAL;
 
                                five_taps = true;
                }
 
                if (width > (2048 >> five_taps))
                        return -EINVAL;
 

-               fclk = calc_fclk(width, height, out_width, out_height,
-                               color_mode, five_taps);
+               if (five_taps)
+                       fclk = calc_fclk_five_taps(width, height,
+                                       out_width, out_height, color_mode);

 
                DSSDBG("required fclk rate = %lu Hz\n", fclk);
                DSSDBG("current fclk rate = %lu Hz\n", dispc_fclk_rate());
 
                DSSDBG("required fclk rate = %lu Hz\n", fclk);
                DSSDBG("current fclk rate = %lu Hz\n", dispc_fclk_rate());