services/surfaceflinger/sysprop/SurfaceFlingerProperties.sysprop

# Copyright (C) 2019 The Android Open Source Project
#
# Licensed under the Apache License, Version 2.0 (the License);
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#      http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an AS IS BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

module: "android.sysprop.SurfaceFlingerProperties"
owner: Platform

# The following two propertiess define (respectively):
#
# - The phase offset between hardware vsync and when apps are woken up by the
#   Choreographer callback
# - The phase offset between hardware vsync and when SurfaceFlinger wakes up
#   to consume input
# Their values may be tuned to trade off between display pipeline latency (both
# overall latency and the lengths of the app --> SF and SF --> display phases)
# and frame delivery jitter (which typically manifests as "jank" or "jerkiness"
# while interacting with the device). The default values must produce a
# relatively low amount of jitter at the expense of roughly two frames of
# app --> display latency, and unless significant testing is performed to avoid
# increased display jitter (both manual investigation using systrace [1] and
# automated testing using dumpsys gfxinfo [2] are recommended), they should not
# be modified.
#
# [1] https://developer.android.com/studio/profile/systrace.html
# [2] https://developer.android.com/training/testing/performance.html
prop {
    api_name: "vsync_event_phase_offset_ns"
    type: Long
    scope: Internal
    access: Readonly
    prop_name: "ro.surface_flinger.vsync_event_phase_offset_ns"
}

prop {
    api_name: "vsync_sf_event_phase_offset_ns"
    type: Long
    scope: Internal
    access: Readonly
    prop_name: "ro.surface_flinger.vsync_sf_event_phase_offset_ns"
}

# Instruct the Render Engine to use EGL_IMG_context_priority hint if available.
prop {
    api_name: "use_context_priority"
    type: Boolean
    scope: Internal
    access: Readonly
    prop_name: "ro.surface_flinger.use_context_priority"
}

# Controls the number of buffers SurfaceFlinger will allocate for use in FramebufferSurface.
prop {
    api_name: "max_frame_buffer_acquired_buffers"
    type: Long
    scope: Internal
    access: Readonly
    prop_name: "ro.surface_flinger.max_frame_buffer_acquired_buffers"
}

# hasWideColorDisplay indicates that the device has
# or can support a wide-color display, e.g. color space
# greater than sRGB. Typical display may have same
# color primaries as DCI-P3.
# Indicate support for this feature by setting
# TARGET_HAS_WIDE_COLOR_DISPLAY to true in BoardConfig.mk
# This also means that the device is color managed.
# A color managed device will use the appropriate
# display mode depending on the content on the screen.
# Default is sRGB.
prop {
    api_name: "has_wide_color_display"
    type: Boolean
    scope: Internal
    access: Readonly
    prop_name: "ro.surface_flinger.has_wide_color_display"
}

# Indicates if Sync framework is available. Sync framework provides fence
# mechanism which significantly reduces buffer processing latency.
prop {
    api_name: "running_without_sync_framework"
    type: Boolean
    scope: Internal
    access: Readonly
    prop_name: "ro.surface_flinger.running_without_sync_framework"
}

# hwHDRDisplay indicates that the device has an High Dynamic Range display.
# A display is considered High Dynamic Range if it
#
#     1. is a wide color gamut display, typically DCI-P3 or lager
#     2. has high luminance capability, typically 540 nits or higher at 10% OPR
#
# Indicate support for this feature by setting
# ro.surface_flinger.has_HDR_display to true in device.mk
# ro.surface_flinger.has_wide_color_display must be set to true when
# ro.surface_flinger.has_HDR_display is true.
prop {
    api_name: "has_HDR_display"
    type: Boolean
    scope: Internal
    access: Readonly
    prop_name: "ro.surface_flinger.has_HDR_display"
}

# Specify the offset in nanoseconds to add to vsync time when timestamping present fences.
prop {
    api_name: "present_time_offset_from_vsync_ns"
    type: Long
    scope: Internal
    access: Readonly
    prop_name: "ro.surface_flinger.present_time_offset_from_vsync_ns"
}

# Some hardware can do RGB->YUV conversion more efficiently in hardware
# controlled by HWC than in hardware controlled by the video encoder.
# This instruct VirtualDisplaySurface to use HWC for such conversion on
# GL composition.
prop {
    api_name: "force_hwc_copy_for_virtual_displays"
    type: Boolean
    scope: Internal
    access: Readonly
    prop_name: "ro.surface_flinger.force_hwc_copy_for_virtual_displays"
}

# Maximum dimension supported by HWC for virtual display.
# Must be equals to min(max_width, max_height).
prop {
    api_name: "max_virtual_display_dimension"
    type: Long
    scope: Internal
    access: Readonly
    prop_name: "ro.surface_flinger.max_virtual_display_dimension"
}

# Return true if surface flinger should use vr flinger for compatible vr
# apps, false otherwise. Devices that will never be running vr apps should
# return false to avoid extra resource usage. Daydream ready devices must
# return true for full vr support.
prop {
    api_name: "use_vr_flinger"
    type: Boolean
    scope: Internal
    access: Readonly
    prop_name: "ro.surface_flinger.use_vr_flinger"
}

# Returns true if surface flinger should start
# hardware.graphics.allocator@2.0::IAllocator service.
prop {
    api_name: "start_graphics_allocator_service"
    type: Boolean
    scope: Internal
    access: Readonly
    prop_name: "ro.surface_flinger.start_graphics_allocator_service"
}

# Returns the orientation of the primary display device.
prop {
    api_name: "primary_display_orientation"
    type: Enum
    enum_values: "ORIENTATION_0|ORIENTATION_90|ORIENTATION_180|ORIENTATION_270"
    scope: Internal
    access: Readonly
    prop_name: "ro.surface_flinger.primary_display_orientation"
}

# useColorManagement indicates whether SurfaceFlinger should manage color
# by switching to appropriate color mode automatically depending on the
# Dataspace of the surfaces on screen.
prop {
    api_name: "use_color_management"
    type: Boolean
    scope: Internal
    access: Readonly
    prop_name: "ro.surface_flinger.use_color_management"
}

# The following four propertiess define:
# Returns the default data space and pixel format that SurfaceFlinger
# expects to receive and output as well as the wide color gamut data space
# and pixel format for wide color gamut surfaces.
# To determine the data space and pixel format, there are a few things
# we recommend to consider:
#
#   1. Hardware composer's capability to composite contents with the chosen
#      data space and pixel format efficiently;
#   2. Hardware composer's ability to composite contents when sRGB contents
#      and the chosen wide color gamut data space contents coexist;
#   3. For better blending, consider using pixel format where the alpha
#      channel has as many bits as the RGB color channel.
#   4. Memory consumption and efficient buffer compression when considering
#      more bits in pixel format.

# dataspace is the default data space that SurfaceFlinger expects.
# The data space must not be Dataspace::UNKNOWN, if unspecified,
# the default data space is Dataspace::V0_SRGB;
prop {
    api_name: "default_composition_dataspace"
    type: Long
    scope: Internal
    access: Readonly
    prop_name: "ro.surface_flinger.default_composition_dataspace"
}

# pixelFormat is the default pixel format that SurfaceFlinger
# expects. If unspecified, the default pixel format is
# PixelFormat::RGBA_8888.
prop {
    api_name: "default_composition_pixel_format"
    type: Integer
    scope: Internal
    access: Readonly
    prop_name: "ro.surface_flinger.default_composition_pixel_format"
}

# wcgDataspace is the data space that SurfaceFlinger expects for
# wide color gamut surfaces.
# When hasWideColorDisplay returns true, this API must return a
# valid wide color gamut data space.
# The data space must not be UNKNOWN, if unspecified, the data space
# is V0_SRGB by default, which essentially indicates there's no wide
# color gamut, meaning hasWideColorDisplay returns false.
prop {
    api_name: "wcg_composition_dataspace"
    type: Long
    scope: Internal
    access: Readonly
    prop_name: "ro.surface_flinger.wcg_composition_dataspace"
}

# wcgPixelFormat is the pixel format that SurfaceFlinger expects for
# wide color gamut surfaces. If unspecified, the pixel format is
# PixelFormat::RGBA_8888 by default.
prop {
    api_name: "wcg_composition_pixel_format"
    type: Integer
    scope: Internal
    access: Readonly
    prop_name: "ro.surface_flinger.wcg_composition_pixel_format"
}