On Fri 11-04-14 08:58:59, Hans Verkuil wrote: > On 04/11/2014 12:18 AM, Jan Kara wrote: > > On Thu 10-04-14 23:57:38, Jan Kara wrote: > >> On Thu 10-04-14 14:22:20, Hans Verkuil wrote: > >>> On 04/10/14 14:15, Jan Kara wrote: > >>>> On Thu 10-04-14 13:07:42, Hans Verkuil wrote: > >>>>> On 04/10/14 12:32, Jan Kara wrote: > >>>>>> Hello, > >>>>>> > >>>>>> On Thu 10-04-14 12:02:50, Marek Szyprowski wrote: > >>>>>>> On 2014-03-17 20:49, Jan Kara wrote: > >>>>>>>> The following patch series is my first stab at abstracting vma handling > >>>>>>> >from the various media drivers. After this patch set drivers have to know > >>>>>>>> much less details about vmas, their types, and locking. My motivation for > >>>>>>>> the series is that I want to change get_user_pages() locking and I want > >>>>>>>> to handle subtle locking details in as few places as possible. > >>>>>>>> > >>>>>>>> The core of the series is the new helper get_vaddr_pfns() which is given a > >>>>>>>> virtual address and it fills in PFNs into provided array. If PFNs correspond to > >>>>>>>> normal pages it also grabs references to these pages. The difference from > >>>>>>>> get_user_pages() is that this function can also deal with pfnmap, mixed, and io > >>>>>>>> mappings which is what the media drivers need. > >>>>>>>> > >>>>>>>> The patches are just compile tested (since I don't have any of the hardware > >>>>>>>> I'm afraid I won't be able to do any more testing anyway) so please handle > >>>>>>>> with care. I'm grateful for any comments. > >>>>>>> > >>>>>>> Thanks for posting this series! I will check if it works with our > >>>>>>> hardware soon. This is something I wanted to introduce some time ago to > >>>>>>> simplify buffer handling in dma-buf, but I had no time to start working. > >>>>>> Thanks for having a look in the series. > >>>>>> > >>>>>>> However I would like to go even further with integration of your pfn > >>>>>>> vector idea. This structure looks like a best solution for a compact > >>>>>>> representation of the memory buffer, which should be considered by the > >>>>>>> hardware as contiguous (either contiguous in physical memory or mapped > >>>>>>> contiguously into dma address space by the respective iommu). As you > >>>>>>> already noticed it is widely used by graphics and video drivers. > >>>>>>> > >>>>>>> I would also like to add support for pfn vector directly to the > >>>>>>> dma-mapping subsystem. This can be done quite easily (even with a > >>>>>>> fallback for architectures which don't provide method for it). I will try > >>>>>>> to prepare rfc soon. This will finally remove the need for hacks in > >>>>>>> media/v4l2-core/videobuf2-dma-contig.c > >>>>>> That would be a worthwhile thing to do. When I was reading the code this > >>>>>> seemed like something which could be done but I delibrately avoided doing > >>>>>> more unification than necessary for my purposes as I don't have any > >>>>>> hardware to test and don't know all the subtleties in the code... BTW, is > >>>>>> there some way to test the drivers without the physical video HW? > >>>>> > >>>>> You can use the vivi driver (drivers/media/platform/vivi) for this. > >>>>> However, while the vivi driver can import dma buffers it cannot export > >>>>> them. If you want that, then you have to use this tree: > >>>>> > >>>>> http://git.linuxtv.org/cgit.cgi/hverkuil/media_tree.git/log/?h=vb2-part4 > >>>> Thanks for the pointer that looks good. I've also found > >>>> drivers/media/platform/mem2mem_testdev.c which seems to do even more > >>>> testing of the area I made changes to. So now I have to find some userspace > >>>> tool which can issue proper ioctls to setup and use the buffers and I can > >>>> start testing what I wrote :) > >>> > >>> Get the v4l-utils.git repository (http://git.linuxtv.org/cgit.cgi/v4l-utils.git/). > >>> You want the v4l2-ctl tool. Don't use the version supplied by your distro, > >>> that's often too old. > >>> > >>> 'v4l2-ctl --help-streaming' gives the available options for doing streaming. > >>> > >>> So simple capturing from vivi is 'v4l2-ctl --stream-mmap' or '--stream-user'. > >>> You can't test dmabuf unless you switch to the vb2-part4 branch of my tree. > >> Great, it seems to be doing something and it shows there's some bug in my > >> code. Thanks a lot for help. > > OK, so after a small fix the basic functionality seems to be working. It > > doesn't seem there's a way to test multiplanar buffers with vivi, is there? > > For that you need to switch to the vb2-part4 branch as well. That has support > for multiplanar. OK, I've merged that branch to my kernel but I failed to find the setting for vivi that would create multiplanar buffers and in fact I don't see multiplanar capabilities among the capabilities reported by the v4l2-ctl tool. Can you help me please? Honza -- Jan Kara <jack@xxxxxxx> SUSE Labs, CR -- 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
