Messages in this thread | | | Date | Fri, 24 Apr 2015 09:17:44 +0200 | From | Greg Kroah-Hartman <> | Subject | Re: [PATCH v2] staging: fbtft: Disable DMA support if DMA is not available |
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On Fri, Apr 24, 2015 at 09:15:00AM +0200, Geert Uytterhoeven wrote: > On Thu, Apr 23, 2015 at 9:17 PM, Greg Kroah-Hartman > <gregkh@linuxfoundation.org> wrote: > > 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. > > Alternatively, I can stick in one more #ifdef, to no longer rely on the compiler > optimization?
That would be better.
thanks,
greg k-h
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