On 10/04/2018 08:12 AM, Hans Verkuil wrote:
On 10/03/18 22:43, Eddie James wrote:
On 09/28/2018 06:30 AM, Hans Verkuil wrote:
On 09/25/2018 09:27 PM, Eddie James 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.
Make the video frames available through the V4L2 streaming interface.
Signed-off-by: Eddie James <eajames@xxxxxxxxxxxxx>
+ }
+
+ video->height = (bottom - top) + 1;
+ video->width = (right - left) + 1;
+ size = video->height * video->width;
It looks like you can actually determine the blanking width/height and
possibly even more detailed information that would be very useful to
show with the DV_TIMINGS ioctls.
Hmm. This information is related to the video signal captured from the
host. That information has nothing to do with the buffer that is
compressed and grabbed by the driver and ultimately provided to
userspace. Isn't the timing information meaningless for JPEG frames?
It helps in debugging. Basically you are implementing a receiver for a
video signal. So if for some reason you cannot support the video timings
that the host sends, then it is very useful to have QUERY_DV_TIMINGS report
as much information about the signal as possible.
BTW, out of curiosity, how are the host video signals connected to the
aspeed? Is it still a VGA video signal?
Looking at product briefs it appears that it is VGA. So I guess the aspeed
'sniffs' the VGA signals from the host and can capture the video that way.
Is that correct?
I believe it is a VGA signal from the host, but the Aspeed Video Engine
somewhat abstracts that away; not all the signal information that the
engine is receiving is available to the BMC interface. I did add the
timing information I could access to the latest patch set. As you say,
it could be useful for debugging if weird things are happening.
Thanks!
Eddie
If so, then this driver is a VGA receiver and should act like that.
The host can configure its VGA transmitter to invalid timings, or weird
values, and you need to be able to handle that in your driver.
Forgot to include this question in my previous reply, sorry for the
additional mail.
No problem! Happy to help.
Regards,
Hans
