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authorMauro Carvalho Chehab <mchehab@redhat.com>2009-04-28 19:12:40 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2009-04-28 19:12:40 -0300
commita129f886d7e7b8e23e339f6ab8065cbf19a7c7cc (patch)
treec14462b96f6bc0cb6db29f306a27fcc640f62812 /linux/Documentation/video4linux
parentdb70e703e55d87b3659e6fb511b201b6d725e737 (diff)
parent157f8eb764c03a0d74db15db98790bca85d5f9dd (diff)
downloadmediapointer-dvb-s2-a129f886d7e7b8e23e339f6ab8065cbf19a7c7cc.tar.gz
mediapointer-dvb-s2-a129f886d7e7b8e23e339f6ab8065cbf19a7c7cc.tar.bz2
merge: http://linuxtv.org/hg/~gliakhovetski/v4l-dvb
From: Mauro Carvalho Chehab <mchehab@redhat.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'linux/Documentation/video4linux')
-rw-r--r--linux/Documentation/video4linux/pxa_camera.txt49
1 files changed, 49 insertions, 0 deletions
diff --git a/linux/Documentation/video4linux/pxa_camera.txt b/linux/Documentation/video4linux/pxa_camera.txt
index b1137f9a5..4f6d0ca01 100644
--- a/linux/Documentation/video4linux/pxa_camera.txt
+++ b/linux/Documentation/video4linux/pxa_camera.txt
@@ -26,6 +26,55 @@ Global video workflow
Once the last buffer is filled in, the QCI interface stops.
+ c) Capture global finite state machine schema
+
+ +----+ +---+ +----+
+ | DQ | | Q | | DQ |
+ | v | v | v
+ +-----------+ +------------------------+
+ | STOP | | Wait for capture start |
+ +-----------+ Q +------------------------+
++-> | QCI: stop | ------------------> | QCI: run | <------------+
+| | DMA: stop | | DMA: stop | |
+| +-----------+ +-----> +------------------------+ |
+| / | |
+| / +---+ +----+ | |
+|capture list empty / | Q | | DQ | | QCI Irq EOF |
+| / | v | v v |
+| +--------------------+ +----------------------+ |
+| | DMA hotlink missed | | Capture running | |
+| +--------------------+ +----------------------+ |
+| | QCI: run | +-----> | QCI: run | <-+ |
+| | DMA: stop | / | DMA: run | | |
+| +--------------------+ / +----------------------+ | Other |
+| ^ /DMA still | | channels |
+| | capture list / running | DMA Irq End | not |
+| | not empty / | | finished |
+| | / v | yet |
+| +----------------------+ +----------------------+ | |
+| | Videobuf released | | Channel completed | | |
+| +----------------------+ +----------------------+ | |
++-- | QCI: run | | QCI: run | --+ |
+ | DMA: run | | DMA: run | |
+ +----------------------+ +----------------------+ |
+ ^ / | |
+ | no overrun / | overrun |
+ | / v |
+ +--------------------+ / +----------------------+ |
+ | Frame completed | / | Frame overran | |
+ +--------------------+ <-----+ +----------------------+ restart frame |
+ | QCI: run | | QCI: stop | --------------+
+ | DMA: run | | DMA: stop |
+ +--------------------+ +----------------------+
+
+ Legend: - each box is a FSM state
+ - each arrow is the condition to transition to another state
+ - an arrow with a comment is a mandatory transition (no condition)
+ - arrow "Q" means : a buffer was enqueued
+ - arrow "DQ" means : a buffer was dequeued
+ - "QCI: stop" means the QCI interface is not enabled
+ - "DMA: stop" means all 3 DMA channels are stopped
+ - "DMA: run" means at least 1 DMA channel is still running
DMA usage
---------