Hi Javier, On Wednesday 02 November 2011 17:33:16 javier Martin wrote: > On 2 November 2011 17:12, Devin Heitmueller wrote: > > I've actually got a very similar issue and have been looking into it > > (an em28xx device on OMAP requiring contiguous physical memory for the > > hardware H.264 encoder). One thing you may definitely want to check > > out is the patch sent earlier today with subject: > > My case is a i.MX27 SoC with its internal H.264 encoder. > > > [PATCH] media: vb2: vmalloc-based allocator user pointer handling > > > > While that patch is intended for videobuf2, you might be able to copy > > the core logic into videobuf-vmalloc. > > I've seen a recent patch by Laurent Pinchart which provides vb2 support for > UVC driver. It might also help: > > [PATCH 2/2] uvcvideo: Use videobuf2-vmalloc
I've finally had time to work on that recently, so you should be able to get all the videobuf2 goodies for free :-) However, the above patch that adds user pointer support in the videobuf2 vmalloc-based allocator only supports memory backed by pages. If you contiguous buffer is in a memory area reserved by the system at boot time, the assumption will not be true. Supporting user pointers with no struct page backing is possible, but will require a new patch for vb2. > > There are other drivers which use USERPTR provided buffers (which are > > allocated as contiguous memory from userland [i.e. vfpe_capture > > accepting buffers from cmemk on the OMAP platform]), but they > > typically do DMA so it's not really useful as an example where you > > have a USB based device. > > > > If you get it working, by all means send the code to the ML so others > > can benefit. > > Sure, though I will need some help because it seems some related frameworks > are not ready for what we want to achieve. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
