Hello Joonyoung,
On 2015-04-24 04:13, Joonyoung Shim wrote:
Hi Tobias,
On 04/23/2015 09:28 PM, Tobias Jakobi wrote:
Hello,
I've noticed some inconsistency in what is currently exported as
'zpos' DRM propery to userspace. Currently we create three planes,
where the zpos maps to the mixer 'win' (is this simply short for
window?).
But this is wrong since the mixer layer configuration is currently
done in this way (in mixer_win_reset()):
layer1 (win[1]) > layer0 (win[0]) > video (win[2])
So layer1 is at the top of our stack, and the video layer is at the
bottom. So regardless on how you interpret the zpos property (0 being
the top, or 0 being bottom), it doesn't give you accurate information
on how the planes are ordered.
I know, actually here zpos doesn't mean order priority of layer, it is
just real hardware layer. Exynos mixer has 3 hardware layer, graphic0
layer, graphic1 layer and video layer, so zpos 0 means graphic0 layer,
zpos 1 means graphic1 layer, zpos 2 means video layer.
I'm aware of that, but that doesn't solve the issue at hand: The 'zpos'
property is completly meaningless at ths point, since it tells the DRM
user absolutely nothing about the z-ordering of the planes. Either that
should be fixed (what I'm looking into) or the property should just be
dropped.
Thanks.
Related to this is the issue of how to blend planes. When should
blending of layer be enabled?
Current mixer codes permit blending about all layers except bottom
layer
(just above background layer).
We probably want to based this on three states:
- which layer are enabled
- which pixelformats are associated to the layers
This idea is ok but as i said, there is blending issue of background
layer.
Any suggestions on how to fix that bg issue?
Ville has pointed out that, under the condition that bg is a simple
color, that it could be exported as a crtc property, see [1]. We would
need another 'bg_enabled' flag as well I guess.
- in which order are the layers (*)
Now we don't permit to change order priority of layer.
That's not what I mean (see my example). What I mean is that it should
make a difference if the layer with alpha-pixelformat is on top of some
layer, or below.
Something like this:
- if layer[i] has non-alpha-pixelformat, don't enable any blending for
that layer
- if layer[i] has alpha-pixelformat, and layer[i] is a the bottom of our
layer-stack, don't enable any blending for that layer (*)
- if layer[i] has alpha-pixelformat, and there exists layer[j] which is
located right below layer[i] in our stack, then enable blending
The configuration in (*) then would be the default setup, when just the
primary plane is enabled, and no other planes are active.
The background would then just become another (virtual) layer.
I hope this is less confusing than my previous description. :)
(*) So in the case of 'layer1 > layer0 > video', layer1 disabled,
layer0/video enabled, layer0 having alpha-pixelformat, we want to
blend layer0 and the video layer (so effectively making layer0
translucent).
I'm trying to come up with a proposition for that issue in the next
days, but it would really help to hear thoughts of you guys.
With best wishes,
Tobias
Thanks.
With best wishes,
Tobias
[1] http://article.gmane.org/gmane.comp.video.dri.devel/127749
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