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

[Zengtao (B)]

>-----Original Message-----
>From: Greg Kroah-Hartman [mailto:gregkh@xxxxxxxxxxxxxxxxxxx]
>Sent: Saturday, March 30, 2019 12:04 AM
>To: Zengtao (B) <prime.zeng@xxxxxxxxxxxxx>
>Cc: labbott@xxxxxxxxxx; sumit.semwal@xxxxxxxxxx;
>devel@xxxxxxxxxxxxxxxxxxxx; Todd Kjos <tkjos@xxxxxxxxxxx>;
>linux-kernel@xxxxxxxxxxxxxxx; dri-devel@xxxxxxxxxxxxxxxxxxxxx;
>linaro-mm-sig@xxxxxxxxxxxxxxxx; Arve HjÃnnevÃg <arve@xxxxxxxxxxx>;
>Joel Fernandes <joel@xxxxxxxxxxxxxxxxx>; Martijn Coenen
><maco@xxxxxxxxxxx>; Christian Brauner <christian@xxxxxxxxxx>
>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