On 10/25/2015 21:16, Ran Shalit wrote: > On Sat, Oct 24, 2015 at 11:38 AM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote: >> >> >> On 10/23/2015 23:57, Ran Shalit wrote: >>> On Tue, Oct 20, 2015 at 9:23 AM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote: >>>> On 10/19/2015 10:26 PM, Ran Shalit wrote: >>>>> Hello, >>>>> >>>>> When writing a device driver for capturing video coming from PCIe, >>>>> does it need to be used as v4l device (video for linux) , ? >>>> >>>> Yes. If you don't then 1) you will never be able to upstream the driver, >>>> 2) any application that wants to use your driver will need custom code to >>>> talk to your driver, 3) it will be a lot more work to write the driver >>>> since you can't use the V4L2 kernel frameworks it provides or ask for >>>> help. >>>> >>>> Basically, by deciding to reinvent the wheel you're screwing over your >>>> customers and yourself. >>>> >>>> Here is a nice PCI(e) template driver that you can use as your starting >>>> point: Documentation/video4linux/v4l2-pci-skeleton.c >>>> >>>> Regards, >>>> >>>> Hans >>> >>> Hi Hans, >>> >>> I now understand, that I will be using media sdk (Intel) which is >>> based on DRM framework, and does not use v4l. >> >> DRM is for video output, not video capture. So this seems irrelevant. >> >>> So I probably need to do some custom driver for delivering video with PCIe. >> >> There is only one linux API for video capture: V4L2. What PCIe card are we >> talking about here? What are you trying to achieve? >> > > I need to capture video from PCIe . The video stream will be delivered > from PC through PCIe to a custom board with Intel cpu using media sdk. > The purpose is to encode the raw video and save the encoded stream to > a file. > I guess I can build some custom driver which waits for frames and > deliver the received frames to the media sdk encoder. So the capture driver captures the video to memory and passes it on to the media sdk for encoding? That's V4L2: that API capures video into memory. So don't reinvent the wheel but use V4L2 for your PCIe driver. > Since media sdk does not use v4l anyway, so I guess such custom driver > is the best under this conditions, Right ? No, use V4L2. What you do with the frame after it has been captured into memory has no relevance to the API you use to capture into memory. Regards, Hans -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
