Hi Javier, On Thursday 17 November 2011 11:55:28 javier Martin wrote: > On 4 November 2011 11:41, Laurent Pinchart wrote: > > 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 > > > > 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. > > Hi Laurent, > thanks for your help. > > I am using dma_declare_coherent_memory() at startup to reserve memory. > Then I use dma_alloc_coherent() in my driver through > 'videobuf2-dma-contig.h' (emma-PrP I've recently submitted). I > understand these functions provide memory backed by pages and you are > referring to the case where you use the 'mem' argument of the kernel > to leave memory unused. Am I right? I think you're right, yes. -- Regards, Laurent Pinchart -- 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
