From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f172.google.com (mail-ig0-f172.google.com [209.85.213.172]) by kanga.kvack.org (Postfix) with ESMTP id 28F226B0038 for ; Fri, 9 May 2014 23:01:58 -0400 (EDT) Received: by mail-ig0-f172.google.com with SMTP id uy17so1901314igb.17 for ; Fri, 09 May 2014 20:01:58 -0700 (PDT) Received: from nm45.bullet.mail.ne1.yahoo.com (nm45.bullet.mail.ne1.yahoo.com. [98.138.120.52]) by mx.google.com with SMTP id k4si1723554igx.11.2014.05.09.20.01.57 for ; Fri, 09 May 2014 20:01:57 -0700 (PDT) Message-ID: <1399690747.69805.YahooMailNeo@web160104.mail.bf1.yahoo.com> Date: Fri, 9 May 2014 19:59:07 -0700 (PDT) From: PINTU KUMAR Reply-To: PINTU KUMAR Subject: [MM]: IOMMU and CMA buffer sharing MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-1615118150-2088370353-1399690747=:69805" Sender: owner-linux-mm@kvack.org List-ID: To: "linux-mm@kvack.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linaro-mm-sig@lists.linaro.org" ---1615118150-2088370353-1399690747=:69805 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Hi,=0A=0AI have some queries regarding IOMMU and CMA buffer sharing.=0A=0AW= e have an embedded linux device (kernel 3.10, RAM: 256Mb) in which camera a= nd codec supports IOMMU but the display does not support IOMMU.=0AThus for = camera capture we are using iommu buffers using ION/DMABUF. But for all dis= play rendering we are using CMA buffers.=0ASo, the question is how to achie= ve buffer sharing (zero-copy) between Camera and Display using only IOMMU?= =0A=0ACurrently we are achieving zero-copy using CMA. And we are exploring = options to use IOMMU.=0ANow we wanted to know which option is better? To us= e IOMMU or CMA?=0A=0AIf anybody have come across these design please share = your thoughts and results.=0A=0A=0AThank You!=0ARegards,=0APintu=0A ---1615118150-2088370353-1399690747=:69805 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: quoted-printable

Hi,<= /div>

I have some queries regarding IOM= MU and CMA buffer sharing.

We have an embedded linux device (kernel 3.10, RAM: 256Mb) in w= hich camera and codec supports IOMMU but the display does not support IOMMU= .

Thus for camera capture we are using iommu= buffers using ION/DMABUF. But for all display rendering we are using CMA b= uffers.

So, the question is how to achieve buffe= r sharing (zero-copy) between Camera and Display using only IOMMU?

Currently we are achievi= ng zero-copy using CMA. And we are exploring options to use IOMMU.

Now we wanted to know which option is be= tter? To use IOMMU or CMA?

If anybody have come across these design please share your thou= ghts and results.

Thank You!

Rega= rds,

Pintu

---1615118150-2088370353-1399690747=:69805-- -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org