Re: [PATCH] video: mx3_camera: Allocate camera object via kzalloc

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Em 20-02-2012 16:23, Fabio Estevam escreveu:
> On Mon, Feb 20, 2012 at 4:17 PM, Guennadi Liakhovetski
> <g.liakhovetski@xxxxxx> wrote:
>> On Mon, 20 Feb 2012, Fabio Estevam wrote:
>>
>>> Align mx3_camera driver with the other soc camera driver implementations
>>> by allocating the camera object via kzalloc.
>>
>> Sorry, any specific reason, why you think this "aligning" is so important?
> 
> Not really.
> 
> Just compared it with all other soc camera drivers I found and
> mx3_camera was the only one that uses "vzalloc"
> 
> Any specific reason that requires mx3_camera to use "vzalloc" instead
> of "kzalloc"?

kzalloc() is more restrictive than vzalloc(). With v*alloc, it will allocate
a virtual memory area, with can be discontinuous, while kzalloc will get
a continuous area.

The DMA logic need to be prepared for virtual memory, if v*alloc() is used
(e. g. using videobuf2-vmalloc).

As it is currently including media/videobuf2-dma-contig.h, I this patch
makes sense on my eyes.

> 
> Tested with kzalloc and it worked fine on my mx31pdk.

If the driver is working with vzalloc, then maybe it is due to some arch-specific
implementation for v*alloc. It shouldn't be working like that.

Regards,
Mauro
> 
> Regards,
> 
> Fabio Estevam
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