drm/i915/skl+: Use scaling amount for plane data rate calculation (v4)
if downscaling is enabled plane data rate increases according to scaling
amount. take scaling amount under consideration while calculating plane
data rate
v2: Address Matt's comments, where data rate was overridden because of
missing else.
v3 (by Matt):
- Add braces to 'else' branch to match kernel coding style
- Adjust final calculation now that skl_plane_downscale_amount()
returns 16.16 fixed point value instead of a decimal fixed point
v4 (by Matt):
- Avoid integer overflow by making sure final multiplication is
treated as 64-bit.
Cc: matthew.d.roper@intel.com
Signed-off-by: Kumar, Mahesh <mahesh1.kumar@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Kumar Mahesh <mahesh1.kumar@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1463695381-21368-1-git-send-email-matthew.d.roper@intel.com
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index ceb1eecd..0827459 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -2997,6 +2997,7 @@
{
struct intel_plane_state *intel_pstate = to_intel_plane_state(pstate);
struct drm_framebuffer *fb = pstate->fb;
+ uint32_t down_scale_amount, data_rate;
uint32_t width = 0, height = 0;
unsigned format = fb ? fb->pixel_format : DRM_FORMAT_XRGB8888;
@@ -3016,15 +3017,19 @@
/* for planar format */
if (format == DRM_FORMAT_NV12) {
if (y) /* y-plane data rate */
- return width * height *
+ data_rate = width * height *
drm_format_plane_cpp(format, 0);
else /* uv-plane data rate */
- return (width / 2) * (height / 2) *
+ data_rate = (width / 2) * (height / 2) *
drm_format_plane_cpp(format, 1);
+ } else {
+ /* for packed formats */
+ data_rate = width * height * drm_format_plane_cpp(format, 0);
}
- /* for packed formats */
- return width * height * drm_format_plane_cpp(format, 0);
+ down_scale_amount = skl_plane_downscale_amount(intel_pstate);
+
+ return (uint64_t)data_rate * down_scale_amount >> 16;
}
/*