Hi,
Maybe VCM is helpful for you. Please refer to the following URL.
http://marc.info/?l=linux-mm&m=129255940319217&w=2
Best regards,
Jonghun Han
Wednesday, February 09, 2011 4:52 PM Hans Verkuil wrote:
> -----Original Message-----
> From: [email protected] [mailto:linux-media-
> [email protected]] On Behalf Of Hans Verkuil
> Sent: Wednesday, February 09, 2011 4:52 PM
> To: Wang, Wen W; Jozef Kruger
> Cc: Kanigeri, Hari K; Iyer, Sundar; Yang, Jianwei; [email protected]
> Subject: Re: Memory allocation in Video4Linux
>
> On Wednesday, February 09, 2011 08:27:27 Wang, Wen W wrote:
> > Hi Hari,
> >
> > You are right. What we need is virtual address.
> >
> > Currently we alloc pages (alloc_pages()) for any request. Store those pages
> > for
> an image buffer into a list. We also manage the virtual address for ISP by
> ourself
> (the range from 0 to 4GB) and the page table for our MMU which is independent
> to
> system MMU page table.
>
> Assuming you are using video4linux for this driver, then you should take a
> look at
> the new videobuf2 framework that will appear in 2.6.39. It is already in the
> media
> tree (http://git.linuxtv.org/media_tree.git, see
> include/media/videobuf2-core.h).
>
> It is much better than the old videobuf framework, and in particular gives
> the driver
> much more control on how memory is allocated and used.
>
> Regards,
>
> Hans
>
> >
> > Thanks
> > Wen
> >
> > >-----Original Message-----
> > >From: Kanigeri, Hari K
> > >Sent: 2011年2月9日 15:22
> > >To: Iyer, Sundar; Wang, Wen W; Yang, Jianwei;
> > >[email protected];
> > >[email protected]
> > >Cc: Jozef Kruger
> > >Subject: RE: Memory allocation in Video4Linux
> > >
> > >
> > >
> > >> -----Original Message-----
> > >> From: [email protected]
> > >> [mailto:[email protected]]
> > >> On Behalf Of Iyer, Sundar
> > >> Sent: Wednesday, February 09, 2011 12:20 PM
> > >> To: Wang, Wen W; Yang, Jianwei; [email protected];
> > >> umg-meego- [email protected]
> > >> Cc: Jozef Kruger
> > >> Subject: Re: [Umg-meego-handset-kernel] Memory allocation in
> > >> Video4Linux
> > >>
> > >> I remember some Continous Memory Allocator (CMA) being iterated
> > >> down a few versions on some mailing lists? IIRC, it is also for
> > >> large buffers and management for video IPs.
> > >
> > >I believe CMA is for allocating physically contiguous memory and from
> > >what Wen mentioned he also needs virtual memory management, which the
> > >IOMMU will provide. Please check the open source discussion on CMA,
> > >the last I heard CMA proposal was shot down.
> > >Reference: http://www.spinics.net/lists/linux-media/msg26875.html
> > >
> > >Wen, how are you currently allocating physical memory ?
> > >
> > >
> > >Thank you,
> > >Best regards,
> > >Hari
> > 翳 .n +% 遍荻 w .n 伐 {炳g n r■ ㄨ&｛ 夸z罐 zf＂
> > 赙z_璁 :+v )撸
> >
> >
>
> --
> Hans Verkuil - video4linux developer - sponsored by Cisco
> --
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