On 4 November 2011 11:41, Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> wrote: > 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 >> > > 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? -- Javier Martin Vista Silicon S.L. CDTUC - FASE C - Oficina S-345 Avda de los Castros s/n 39005- Santander. Cantabria. Spain +34 942 25 32 60 www.vista-silicon.com -- 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
