Feature/custom userptr allocator to take into account special hardware-aligment requirements for some v4l devices #103
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This is usefull for devices where there are specific alignment requirements of the memory being written to by the V4L subsystem. One example where this is the case is the CSI-camera support Nvidia Tegra devices.
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Hi, sorry for the delayed response. I agree something along these lines is needed for the cases you mention. Though I think I would prefer a less invasive approach - let the user provide the memory. The library should provide the memory constraints (e.g. size, caching etc) and take in memory provided by the application. This mandates a minor re-architecture that I'm working on at the moment. There have been attempts in the past, but I never got around to finish the work and release it. Let's see whether it can be done this time without being drowned in other real-life events (or vacation ..) |
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Hi. Yeah, letting the client application supply the memory is a better overall architecture. The reason my MR is as it is is that I was afraid to create a large architectural change. |
Hi there.
When using the userptr io-mode for V4L, the v4l driver can have special alignment requirements for the buffers that are given to it.
I hit this limitation by experimenting with the V4L2 drivers for CSI cameras on Nvidia Tegra devices.
This PR tries to allow for specifying custom allocators for the crate in a backward compatible way, and I thought it would be nice to contribute it back to upstream.
If there are any things you would like different, or require changes, please don't hesitate to mention it.
I was unsure where to base this change on, so I based it on the last released version of the crate. I see that
mainhas moved since then.Regards Morten