# Re: \[PATCH 0/5\] OMAPFB: use dma\_alloc instead of omap's vram

- From: Tomi Valkeinen \<hidden\>
- Date: 2012-11-22 13:52:21 
- List: linux-fbdev
- Page: https://ratatoskr.run/linux-fbdev/2012/11/8626442
- Thread: https://ratatoskr.run/linux-arm-kernel/2012/11/8624645/t.md

```text
Hi,

On 2012-11-21 16:22, Jello huang wrote:
> HI Tomi,
> we need  one rank of cma to allocate the memory for driver in kernel
> space .And the default CMA is for allocating memory frome usespace.So
> if we allocate the memory from the
> default CMA zone ,there maybe introduce fragmention to the default CMA
> zone.The kernel space memory donot touch the memory from userspace

Can you elaborate a bit? I didn't understand your point. Are you saying
each kernel driver that uses dma_alloc should have their own CMA zone?
That doesn't make sense...

How do you allocate CMA memory from userspace?

 Tomi


```

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