Re: [PATCH 4/4] media: platform: Add Aspeed Video Engine driver

From: Eddie James
Date: Thu Aug 30 2018 - 11:40:40 EST

On 08/29/2018 07:52 PM, Ezequiel Garcia wrote:
Hi Eddie,

On 29 August 2018 at 18:09, Eddie James <eajames@xxxxxxxxxxxxxxxxxx> wrote:
The Video Engine (VE) embedded in the Aspeed AST2400 and AST2500 SOCs
can capture and compress video data from digital or analog sources. With
the Aspeed chip acting a service processor, the Video Engine can capture
the host processor graphics output.

Add a V4L2 driver to capture video data and compress it to JPEG images,
making the data available through a standard read interface.

Signed-off-by: Eddie James <eajames@xxxxxxxxxxxxxxxxxx>
drivers/media/platform/Kconfig | 8 +
drivers/media/platform/Makefile | 1 +
drivers/media/platform/aspeed-video.c | 1307 +++++++++++++++++++++++++++++++++
3 files changed, 1316 insertions(+)
create mode 100644 drivers/media/platform/aspeed-video.c

diff --git a/drivers/media/platform/Kconfig b/drivers/media/platform/Kconfig
index 94c1fe0..e599245 100644
--- a/drivers/media/platform/Kconfig
+++ b/drivers/media/platform/Kconfig
@@ -32,6 +32,14 @@ source "drivers/media/platform/davinci/Kconfig"

source "drivers/media/platform/omap/Kconfig"

+ tristate "Aspeed AST2400 and AST2500 Video Engine driver"
+ depends on VIDEO_V4L2
It seems you are not using videobuf2. I think it should simplify the read
I/O part and at the same time expose the other capture methods.


Well I'm not sure it would simplify the read interface; it's quite simple as it is, both in the driver and to set up in user-space.

I did get streaming I/O working but found the performance significantly worse than simple read calls, and therefore not worth the additional complexity.

Is it required that I support streaming?


There are plenty of examples to follow.