79
| Date post: | 10-May-2015 |
| Category: |
Technology |
| Upload: | anne-nicolas |
| View: | 1,365 times |
| Download: | 9 times |
Problem Definition
display /
/ graphics /
/ video
Problem - Purpose
display / graphics / video
format
memory / deep pipeline
device / CPU
Problem - Source
formatmemory / deep pipeline
device / CPU
rotation /
/ scaling /
/ composing
Problem - Processing
rotationscaling
composing
X11 /
/ Wayland /
/ MIR /
/ SDL /
/ DirectFB /
/ Raw API
Problem - Stack
X11Wayland
SDLDirectFBRaw API
DRM /
/ FBDEV /
/ V4L2
Problem - API
DRMFBDEVV4L2
Display – Scanout
Frame Buffer
Display – Composition
CRTC
Plane(s)
Composition
Origins
Origins – FBDEV
FBDEV, L
inux 1
.3.9
4
1996 2012
4CC F
orm
ats
2000
Blankin
g
Origins – V4L2
V4L, L
inux 2
.2.0
1999 2002 2006
V4L2,
Linu
x 2.4
.0
V4L d
epre
cate
d
2008
V4L2
subd
ev
2011
Med
ia co
ntro
ller
video
buf2
2012
DMABUF
Origins – DRM/KMS
2000
DRM, L
inux 2
.2.1
8
2009
KMS, T
TM
2008
GEMPlan
es, D
MABUF
2011 2012
Dumb
Buffe
rs
Features
Memory Management
DRM FB V4L2
Dynamic Allocation Yes No Yes
Multiple Buffers Yes panning Yes
Import dmabuf No userptr
Exportdmabufmmap
mmap mmap
Mode Setting
DRM FB V4L2
Formats 4CCRGB4CC
4CC
Enumeration Planes No Yes
Negotiation No No Yes
Atomicity Yes No No
Transformations
DRM FB V4L2
Overlays Yes No Yes
Rotation Yes No Yes
Scaling Yes No Yes
Cropping/Panning Yes Yes Yes
Documentation
api core drivers
drmfbv4l2
DRM API Documentation
The DRM core exports several interfaces to applications, generally intended to be used through corresponding libdrm wrapper functions. In addition, drivers export device-specific interfaces for use by userspace drivers & device-aware applications through ioctls and sysfs files.
External interfaces include: memory mapping, context management, DMA operations, AGP management, vblank control, fence management, memory management, and output management.
Cover generic ioctls and sysfs layout here. We only need high-level info, since man pages should cover the rest.
“
„
Documentation
api core drivers
drmfbv4l2
Code Size
api core drivers
drmfbv4l2
Cumulative Changes - API
0
1000
2000
3000
4000
5000
6000
drm
fb
v4l2
drmfbv4l2
Cumulative Changes - Core
0
5000
10000
15000
20000
25000
30000
35000
40000
45000
50000
drm
fb
v4l2
drmfbv4l2
Cumulative Changes - Drivers
0
200000
400000
600000
800000
1000000
1200000
1400000
1600000
1800000
drm
fb
v4l2
drmfbv4l2
Mailing List Traffic
0
200
400
600
800
1000
1200
1400
1600
1800
drmfbv4l2drm+bug
Device Model – FBDEV
Frame Buffer(memory)
DisplayDevice
Device Model – DRM/KMS
Frame Buffer(memory) CRTC Encoder Connector
Planes(memory)
Encoder
Connector
Connector
Device Model – V4L2
Buffers(memory)
DisplayDevice
Connector
Device Model – V4L2/MC
V4L2subdev
0
1
2V4L2
subdev0 1
V4L2queue
0
Device Model – V4L2/MC
Use Cases
Use Cases - FBDEV
Use Cases - FBDEV
(that's it...)
Use Cases - V4L2
Video
Use Cases – DRM/KMS
Everything else
FB vs. DRM - sloccount
fbdev0
500
1000
1500
2000
2500
2370
FB vs. DRM - sloccount
fbdev drm0
500
1000
1500
2000
2500
2370
1659
DRM/KMS API
drmkmsexynosi810i915mganouveaur128radeonsavagesisvia
KMS - Device Model
Frame Buffer(memory) CRTC Encoder Connector
Plane(memory)
SoCMemory Off-Chip
Encoder Connector
KMS – Frame Buffer
CRTC
Frame Buffer
GEMObject(s)
Memory
● width● height● format● pitches● offsets
Properties
DRM/KMS – GEM Object
CRTC
Frame Buffer
GEM Object
● width● height● bpp● pitch● size
Properties
Memory
DRM – Handles
Process A
LocalHandle
GEMObject
Process B
Send FDSCM_RIGHTS
GlobalFD
1 2Global
FD4
LocalHandle
3
ActiveArea
KMS – Modes (1/2)
sync
back porch
front porch
active area
ActiveArea
KMS – Modes (2/2)
sync
back porch
front porch
active area
hdisplayhsync_start
htotal
hsync_end
KMS – Mode Setting
crtc
fb
ActiveArea
x
y
mode.hdisplay
mo
de
. vdisp
l ay
*connectorsnum_connectors
mode
struct drm_mode_set { struct drm_framebuffer *fb; struct drm_crtc *crtc; struct drm_display_mode *mode; uint32_t x; uint32_t y; struct drm_connector **connectors; size_t num_connectors;};
Source: http://www.flickr.com/photos/buckaroobay/3721809183/
WIP – Display Framework
Common Display Framework
http://lwn.net/Articles/512363/
Entity
Entity
Link Port
CDF - Entity Model
CDF - Device Tree
hdmi_encoder { ports { #address-cells = <1>; #size-cells = <0>;
port@0 { hdmi_input: endpoint@0 { remote = <&display_output>; }; }; port@1 { endpoint@0 { ... }; endpoint@1 { ... }; }; };};
Display Controller
VideoEntity
Pipeline Controller
controlcontrol
Entity Entity
CDF - Configuration Model
Display Controller
VideoEntity
streaming control
streaming control
Entity Entity
CDF - Streaming Control
CDF - Integration
DisplayController
DriverControl Bus API
FBDEV DRM
SPI/I2C Mem Map
Panel Driver
DT
pdata
DSI
? !
merci.
