amdgpu/display/mpo-overview.rst

6    'Documentation/gpu/amdgpu/display/dcn-overview.rst'.
10 fixed-function hardware in the display controller rather than using graphics or
12 the graphics/compute pipelines can be put into low-power states. In summary,
15 * Decreased GPU and CPU workload - no composition shaders needed, no extra
17 * Plane independent page flips - No need to be tied to global compositor
18   page-flip present rate, reduced latency, independent timing.
20 .. note:: Keep in mind that MPO is all about power-saving; if you want to learn
21    more about power-save in the display context, check the link:
22    `Power <https://gitlab.freedesktop.org/pq/color-and-hdr/-/blob/main/doc/power.rst>`__.
26 (modesetting, page-flipping, etc) - drmModeAtomicCommit. To query hardware
36 * ``DRM_PLANE_TYPE_OVERLAY``: Overlay planes represent all non-primary,
37   non-cursor planes. Some drivers refer to these types of planes as "sprites"
51 means, look at 'Documentation/gpu/amdgpu/display/dcn-overview.rst', section
52 "AMD Hardware Pipeline"). Typically most AMD devices operate in a pipe-split
55 A typical MPO configuration from userspace - 1 primary + 1 overlay on a single
56 display - will see 4 pipes in use, 2 per plane.
60 limit of 4 planes across all CRTCs. Atomic commits will be rejected for display
70 Atomic commits will be rejected for commits which do not follow these
80 * Only primary planes have color-space and non-RGB format support
89 .. kernel-figure:: mpo-cursor.svg
108 Picture-in-Picture (PIP) playback - Underlay strategy
109 -----------------------------------------------------
117   - The overlay plane contains general desktop UI, video player controls, and video subtitles
118   - Primary plane contains one or more videos
124 See below a single-video example:
126 .. kernel-figure:: single-display-mpo.svg
142 plane's framebuffer is used for standard double-buffered playback.
161 - ``kms_plane@plane-panning-bottom-right-pipe-*-planes``
162 - ``kms_plane@plane-panning-bottom-right-suspend-pipe-*-``
163 - ``kms_plane@plane-panning-top-left-pipe-*-``
164 - ``kms_plane@plane-position-covered-pipe-*-``
165 - ``kms_plane@plane-position-hole-dpms-pipe-*-``
166 - ``kms_plane@plane-position-hole-pipe-*-``
167 - ``kms_plane_multiple@atomic-pipe-*-tiling-``
168 - ``kms_plane_scaling@pipe-*-plane-scaling``
169 - ``kms_plane_alpha_blend@pipe-*-alpha-basic``
170 - ``kms_plane_alpha_blend@pipe-*-alpha-transparant-fb``
171 - ``kms_plane_alpha_blend@pipe-*-alpha-opaque-fb``
172 - ``kms_plane_alpha_blend@pipe-*-constant-alpha-min``
173 - ``kms_plane_alpha_blend@pipe-*-constant-alpha-mid``
174 - ``kms_plane_alpha_blend@pipe-*-constant-alpha-max``
177 --------------------
184 many more restrictions for a multi-display scenario. The below example shows a
188 .. kernel-figure:: multi-display-hdcp-mpo.svg
191 multi-display with MPO.
207 - 1 display (1 pipe) + MPO (1 pipe), we will use two pipes
208 - 2 displays (2 pipes) + MPO (1-2 pipes); we will use 4 pipes. MPO in the
210 - 3 Displays (3 pipes) + MPO (1-2 pipes), we need 5 pipes.
223 .. kernel-figure:: multi-display-hdcp-mpo-less-pipe-ex.svg
225 - Total pipes are 3
226 - User lights up 2 displays (2 out of 3 pipes are used)
227 - User launches video (1 pipe used for MPO)
228 - Now, if the user moves the video in the middle of 2 displays, one part of the