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Re: Can't allocate DMA buffer



> 
> Hi,
> 
> I'm running the most recent kernel (2.2.7), and I also use a Crystal
> semiconductor sound card, so I have the cs4232 kernel module.  Sometimes I
> get the kernel error: 
> 
>   kernel: Sound error: Couldn't allocate DMA buffer
> 
> I have plenty of available memory left, so I don't understand why I am
> getting this error.  Has anybody else received this error?  Does anybody
> know of a workaround or fix for it?  I haven't received this error before
> installing the 2.2.7 kernel.

I have had this error with kernels from the 2.0.x series.  My floppy
drive also has this problem sometimes.  The problem is that apparently
the DMA buffer needs to be allocated in the first 16MB of address
space.  In my view, the driver should reserve enough of this memory
when it is loaded, but this may be a problem if it is not loaded at
boot time (but later, as a module).  I once asked around on a linux
kernel news group, and people were thinking about how to reorganise the
DMA memory.  It doesn't seem to be trivial to solve.  A `solution'
would be to get a PCI sound card.  Often you get around the problem
stopping some applications hoping to free some of the `right' memory :(

HTH,
Eric Meijer

-- 
 E.L. Meijer (tgakem@chem.tue.nl)
 Eindhoven Univ. of Technology
 Lab. for Catalysis and Inorg. Chem. (SKA)


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