The patch number 11613 was added via Guennadi Liakhovetski
<g.liakhovet...@gmx.de>
to http://linuxtv.org/hg/v4l-dvb master development tree.
Kernel patches in this development tree may be modified to be backward
compatible with older kernels. Compatibility modifications will be
removed before inclusion into the mainstream Kernel
If anyone has any objections, please let us know by sending a message to:
Linux Media Mailing List <linux-me...@vger.kernel.org>
------
From: Robert Jarzmik <robert.jarz...@free.fr>
pxa_camera: Documentation of the FSM
After DMA redesign, the pxa_camera dynamic behaviour should
be documented so that future contributors understand how it
works, and improve it.
Signed-off-by: Robert Jarzmik <robert.jarz...@free.fr>
Signed-off-by: Guennadi Liakhovetski <g.liakhovet...@gmx.de>
---
Documentation/video4linux/pxa_camera.txt | 49 ++++++++++++++++++++++++++++++
1 files changed, 49 insertions(+), 0 deletions(-)
---
linux/Documentation/video4linux/pxa_camera.txt | 49 +++++++++++++++++
1 file changed, 49 insertions(+)
diff -r 4a2b85d095d4 -r 0a2cba7f41c6
linux/Documentation/video4linux/pxa_camera.txt
--- a/linux/Documentation/video4linux/pxa_camera.txt Fri Apr 24 17:58:24
2009 +0200
+++ b/linux/Documentation/video4linux/pxa_camera.txt Fri Apr 24 17:58:35
2009 +0200
@@ -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
---------
---
Patch is available at:
http://linuxtv.org/hg/v4l-dvb/rev/0a2cba7f41c6f2a05b0cd01875d37d4e470b6b32
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