Shield Console - Android TV - Reports physical display size as 1080p, not 2160p

I have the Shield Console connected to a Samsung 4K TV. The Samsung TV shows that the Shield Console is driving 2160p60 over HDMI. So far so good. However, when I query the physical display size in Android, I get 1080p.

Here is the output of “dumpsys display”

mDefaultViewport=DisplayViewport{valid=true, displayId=0, orientation=0, logicalFrame=Rect(0, 0 - 1920, 1080), physicalFrame=Rect(0, 0 - 1920, 1080), deviceWidth=1920, deviceHeight=1080}

If I decode a 4K movie, Surface Flinger shows that the 4K decoder output is scaled down to 1080p. At some point in the pipeline it must be scaled back up to 4K, because that is what the Samsung TV sees.

Is this really what Android TV on the Shield Console is doing? Or am I somehow misinterpreting dumpsys display and dumpsys SurfaceFlinger. Other experiments seem to confirm this is what Android TV is doing.

Can someone verify that 4K decoded content is preserved throughout the Android media pipeline?