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: linux-media-owner@xxxxxxxxxxxxxxx [mailto:linux-media- > owner@xxxxxxxxxxxxxxx] 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; linux-media@xxxxxxxxxxxxxxx > 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: 2011å2æ9æ 15:22 > > >To: Iyer, Sundar; Wang, Wen W; Yang, Jianwei; > > >linux-media@xxxxxxxxxxxxxxx; > > >umg-meego-handset-kernel@xxxxxxxxxxxxxxxxxxxxxxx > > >Cc: Jozef Kruger > > >Subject: RE: Memory allocation in Video4Linux > > > > > > > > > > > >> -----Original Message----- > > >> From: umg-meego-handset-kernel-bounces@xxxxxxxxxxxxxxxxxxxxxxx > > >> [mailto:umg-meego-handset-kernel-bounces@xxxxxxxxxxxxxxxxxxxxxxx] > > >> On Behalf Of Iyer, Sundar > > >> Sent: Wednesday, February 09, 2011 12:20 PM > > >> To: Wang, Wen W; Yang, Jianwei; linux-media@xxxxxxxxxxxxxxx; > > >> umg-meego- handset-kernel@xxxxxxxxxxxxxxxxxxxxxxx > > >> 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 > > ç .n +% éè w .n ä {çg î n râ ãî&ï åzç zfï > > èz_ç :+v î)æ > > > > > > -- > Hans Verkuil - video4linux developer - sponsored by Cisco > -- > 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 -- 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
