Re: [PATCH v2] staging: fbtft: Disable DMA support if DMA is not available

[Greg Kroah-Hartman]

On Thu, Apr 23, 2015 at 08:47:15PM +0200, Geert Uytterhoeven wrote:
> If NO_DMA=y:
> 
>     drivers/built-in.o: In function `fbtft_framebuffer_alloc':
>     (.text+0xb53cae): undefined reference to `dmam_alloc_coherent'
> 
> As DMA support is already optional, make it depend on HAS_DMA.
> 
> If !HAS_DMA, "dma" will always be false, and the compiler will optimize
> away the call to dmam_alloc_coherent().

Oh that's "sneaky" and not good, let's just make this driver be
dependant on DMA and be done with it.  I don't like to rely on the
optimizer to get things to work properly.

thanks,

greg k-h
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