gma500: Be smarter about layout

If we can't fit a page aligned display stride then it's not the end of the
world for a normal font, so try half a page and work down sizes.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

diff --git a/drivers/gpu/drm/gma500/framebuffer.c b/drivers/gpu/drm/gma500/framebuffer.c
index 652f1ec..9ec1676 100644 (file)
--- a/drivers/gpu/drm/gma500/framebuffer.c
+++ b/drivers/gpu/drm/gma500/framebuffer.c
@@ -385,7 +385,8 @@ static int psbfb_create(struct psb_fbdev *fbdev,
        int ret;
        struct gtt_range *backing;
        u32 bpp, depth;
-       int gtt_roll = 1;
+       int gtt_roll = 0;
+       int pitch_lines = 0;
 
        mode_cmd.width = sizes->surface_width;
        mode_cmd.height = sizes->surface_height;
@@ -395,27 +396,40 @@ static int psbfb_create(struct psb_fbdev *fbdev,
        if (bpp == 24)
                bpp = 32;
 
-       /* Acceleration via the GTT requires pitch to be 4096 byte aligned 
-          (ie 1024 or 2048 pixels in normal use) */
-       mode_cmd.pitches[0] =  ALIGN(mode_cmd.width * ((bpp + 7) / 8), 4096);
-       depth = sizes->surface_depth;
+       do {
+               /*
+                * Acceleration via the GTT requires pitch to be
+                * power of two aligned. Preferably page but less
+                * is ok with some fonts
+                */
+               mode_cmd.pitches[0] =  ALIGN(mode_cmd.width * ((bpp + 7) / 8), 4096 >> pitch_lines);
+               depth = sizes->surface_depth;
+
+               size = mode_cmd.pitches[0] * mode_cmd.height;
+               size = ALIGN(size, PAGE_SIZE);
+
+               /* Allocate the fb in the GTT with stolen page backing */
+               backing = psbfb_alloc(dev, size);
+
+               if (pitch_lines)
+                       pitch_lines *= 2;
+               else
+                       pitch_lines = 1;
+               gtt_roll++;
+       } while (backing == NULL && pitch_lines <= 16);
 
-       size = mode_cmd.pitches[0] * mode_cmd.height;
-       size = ALIGN(size, PAGE_SIZE);
+       /* The final pitch we accepted if we succeeded */
+       pitch_lines /= 2;
 
-       /* Try and allocate with the alignment we need */
-       backing = psbfb_alloc(dev, size);
        if (backing == NULL) {
                /*
                 *      We couldn't get the space we wanted, fall back to the
                 *      display engine requirement instead.  The HW requires
                 *      the pitch to be 64 byte aligned
-                *
-                *      FIXME: We could try alignments in a loop so that we can still
-                *      accelerate power of two font sizes.
                 */
 
                gtt_roll = 0;   /* Don't use GTT accelerated scrolling */
+               pitch_lines = 64;
 
                mode_cmd.pitches[0] =  ALIGN(mode_cmd.width * ((bpp + 7) / 8), 64);
 
@@ -452,12 +466,12 @@ static int psbfb_create(struct psb_fbdev *fbdev,
        strcpy(info->fix.id, "psbfb");
 
        info->flags = FBINFO_DEFAULT;
-       if (gtt_roll) { /* GTT rolling seems best */
+       if (dev_priv->ops->accel_2d && pitch_lines > 8) /* 2D engine */
+               info->fbops = &psbfb_ops;
+       else if (gtt_roll) {    /* GTT rolling seems best */
                info->fbops = &psbfb_roll_ops;
                info->flags |= FBINFO_HWACCEL_YPAN;
-        } else if (dev_priv->ops->accel_2d)    /* 2D engine */
-               info->fbops = &psbfb_ops;
-       else    /* Software */
+       } else  /* Software */
                info->fbops = &psbfb_unaccel_ops;
 
        ret = fb_alloc_cmap(&info->cmap, 256, 0);