drm/i915: Simplify SWIDTHSW calculation

The formula in Bspec for computing the overlay SWIDTHSW is overly
obfuscated. Simplify the formula to something that's easily parsed by
humans.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1481131693-27993-8-git-send-email-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
This commit is contained in:
Ville Syrjälä 2016-12-07 19:28:09 +02:00
parent 949d8cf801
commit 7039a6dc17

View File

@ -567,19 +567,17 @@ static int uv_vsubsampling(u32 format)
static u32 calc_swidthsw(struct drm_i915_private *dev_priv, u32 offset, u32 width)
{
u32 mask, shift, ret;
if (IS_GEN2(dev_priv)) {
mask = 0x1f;
shift = 5;
} else {
mask = 0x3f;
shift = 6;
}
ret = ((offset + width + mask) >> shift) - (offset >> shift);
if (!IS_GEN2(dev_priv))
ret <<= 1;
ret -= 1;
return ret << 2;
u32 sw;
if (IS_GEN2(dev_priv))
sw = ALIGN((offset & 31) + width, 32);
else
sw = ALIGN((offset & 63) + width, 64);
if (sw == 0)
return 0;
return (sw - 32) >> 3;
}
static const u16 y_static_hcoeffs[N_HORIZ_Y_TAPS * N_PHASES] = {