RE: [PATCH] staging: android: ion: refactory ion_alloc for kernel driver use

Zengtao (B)
2019-03-30T02:32:45Z

>-----Original Message-----
>From: Greg Kroah-Hartman [mailto:gregkh@linuxfoundation.org]
>Sent: Saturday, March 30, 2019 12:04 AM
>To: Zengtao (B) <prime.zeng@hisilicon.com>
>Cc: labbott@redhat.com; sumit.semwal@linaro.org;
>devel@driverdev.osuosl.org; Todd Kjos <tkjos@android.com>;
>linux-kernel@vger.kernel.org; dri-devel@lists.freedesktop.org;
>linaro-mm-sig@lists.linaro.org; Arve Hjønnevåg <arve@android.com>;
>Joel Fernandes <joel@joelfernandes.org>; Martijn Coenen
><maco@android.com>; Christian Brauner <christian@brauner.io>
>Subject: Re: [PATCH] staging: android: ion: refactory ion_alloc for kernel
>driver use
>
>On Sat, Mar 30, 2019 at 02:40:16AM +0800, Zeng Tao wrote:
>> There are two reasons for this patch:
>> 1. There are some potential requirements for ion_alloc in kernel
>> space, some media drivers need to allocate media buffers from ion
>> instead of buddy or dma framework, this is more convient and clean
>> very for media drivers. And In that case, ion is the only media buffer
>> provider, it's more easier to maintain.
>
>As this really is just DMA, what is wrong with the existing dma framework
>that makes it hard to use? You have seen all of the changes recently to it,
>right?

The current dma framework is powerful enough(to me, and more complex ^_^)
, CMA, IOMMU are all integrated, it's good. But buffer sharing, statistics, debug,
are not so friendly for media drivers(each driver has to do all, but duplicate jobs).

>
>thanks,
>
>greg k-h