Here's a first attempt at allowing IO memory for USERPTR buffers. It also fixes another issue: it was assumed that dma->sglen == dma->nr_pages. I'll split that up in a separate patch in the final version. Regards, Arnout On Wednesday 03 March 2010 15:12:44, Arnout Vandecappelle wrote: > Hoi, > > [Please CC me, I'm not subscribed.] > > I'm implementing zerocopy transfer from a v4l2 camera to the DSP on an > OMAP3 (based on earlier work by Stefan Kost [1][2]). Therefore I'm using > V4L2_MEMORY_USERPTR to pass in the memory area allocated by TI's DMAI > driver. However, this has flags VM_IO | VM_PFNMAP. This means that it > is not possible to do get_user_pages() on it - it's an area that is not > pageable and possibly even doesn't pass the MMU. > > In order to support this kind of zerocopy construct, I propose to add > checks for VM_IO | VM_PFNMAP and only get pages from areas that don't > have these flags set. > > If I get positive feedback on this, I'll supply a patch. > > > [1] https://bugzilla.gnome.org/show_bug.cgi?id=583890 > [2] http://thread.gmane.org/gmane.linux.drivers.video-input- > infrastructure/6209 -- Arnout Vandecappelle arnout at mind be Senior Embedded Software Architect +32-16-286540 Essensium/Mind http://www.mind.be G.Geenslaan 9, 3001 Leuven, Belgium BE 872 984 063 RPR Leuven LinkedIn profile: http://www.linkedin.com/in/arnoutvandecappelle GPG fingerprint: 31BB CF53 8660 6F88 345D 54CC A836 5879 20D7 CF43 -- 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
