Re: CMA broken in next-20120926

[Andrew Morton]

On Thu, 27 Sep 2012 13:29:11 +0200
Thierry Reding <thierry.reding@xxxxxxxxxxxxxxxxx> wrote:

> Hi Marek,
> 
> any idea why CMA might be broken in next-20120926. I see that there
> haven't been any major changes to CMA itself, but there's been quite a
> bit of restructuring of various memory allocation bits lately. I wasn't
> able to track the problem down, though.
> 
> What I see is this during boot (with CMA_DEBUG enabled):
> 
> [    0.266904] cma: dma_alloc_from_contiguous(cma db474f80, count 64, align 6)
> [    0.284469] cma: dma_alloc_from_contiguous(): memory range at c09d7000 is busy, retrying
> [    0.293648] cma: dma_alloc_from_contiguous(): memory range at c09d7800 is busy, retrying
> ...
> [    2.648619] DMA: failed to allocate 256 KiB pool for atomic coherent allocation
> ...
> [    4.196193] WARNING: at /home/thierry.reding/src/kernel/linux-ipmp.git/arch/arm/mm/dma-mapping.c:485 __alloc_from_pool+0xdc/0x110()
> [    4.207988] coherent pool not initialised!
> 
> So the pool isn't getting initialized properly because CMA can't get at
> the memory. Do you have any hints as to what might be going on? If it's
> any help, I started seeing this with next-20120926 and it is in today's
> next as well.
> 

Bart and Minchan have made recent changes to CMA.  Let us cc them.


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