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
