CONFIG_ISA_DMA_API without CONFIG_GENERIC_ISA_DMA

CONFIG_ISA_DMA_API without CONFIG_GENERIC_ISA_DMA

[Scott Wood]

I tried building a kernel using mpc85xx_smp_defconfig, but with all 
platforms but p4080ds removed.  This was the result:

>   LD      .tmp_vmlinux1
> sound/built-in.o: In function `claim_dma_lock':
> /home/scott/git/fsl/linux/upstream/arch/powerpc/include/asm/dma.h:179: undefined reference to `dma_spin_lock'
> /home/scott/git/fsl/linux/upstream/arch/powerpc/include/asm/dma.h:179: undefined reference to `dma_spin_lock'
> /home/scott/git/fsl/linux/upstream/arch/powerpc/include/asm/dma.h:179: undefined reference to `dma_spin_lock'
> /home/scott/git/fsl/linux/upstream/arch/powerpc/include/asm/dma.h:179: undefined reference to `dma_spin_lock'
> /home/scott/git/fsl/linux/upstream/arch/powerpc/include/asm/dma.h:179: undefined reference to `dma_spin_lock'
> sound/built-in.o:/home/scott/git/fsl/linux/upstream/arch/powerpc/include/asm/dma.h:179: more undefined references to `dma_spin_lock' follow
> make: *** [.tmp_vmlinux1] Error 1

Commit fb4f0e8832e0075849b41b65f6bb9fdfa7593b99 (Enable GENERIC_ISA_DMA 
if FSL_ULI1575 to fix compile issue) tries to deal with this, but it 
ties it to CONFIG_FSL_ULI1575, which is not selected in a p4080ds-only 
config.

It seems that ULI isn't really relevant to the actual problem, which is 
that we enable ISA DMA API support without selecting an implementation. 
  Whether a certain chip is on the board that has an actual ISA 
interface is irrelevant to the build breakage.

Where did the dependency list for GENERIC_ISA_DMA come from?  Are there 
any legitimate cases on powerpc where we want to select ISA_DMA_API but 
not GENERIC_ISA_DMA (i.e. we have an alternate implementation)?

-Scott

Re: CONFIG_ISA_DMA_API without CONFIG_GENERIC_ISA_DMA

[Timur Tabi]

On Thu, Feb 25, 2010 at 3:40 PM, Scott Wood <scottwood@freescale.com> wrote=
:
> Commit fb4f0e8832e0075849b41b65f6bb9fdfa7593b99 (Enable GENERIC_ISA_DMA i=
f
> FSL_ULI1575 to fix compile issue) tries to deal with this, but it ties it=
 to
> CONFIG_FSL_ULI1575, which is not selected in a p4080ds-only config.
>
> It seems that ULI isn't really relevant to the actual problem, which is t=
hat
> we enable ISA DMA API support without selecting an implementation. =A0Whe=
ther
> a certain chip is on the board that has an actual ISA interface is
> irrelevant to the build breakage.
>
> Where did the dependency list for GENERIC_ISA_DMA come from? =A0Are there=
 any
> legitimate cases on powerpc where we want to select ISA_DMA_API but not
> GENERIC_ISA_DMA (i.e. we have an alternate implementation)?

I've been bitten by this issue as well on the P1022DS.  If I enable
ALSA, then some ISA support also gets compile (by itself, that's
probably a bug), and that code calls claim_dma_lock().

This problem's been around for a long time.  I would have encountered
it on the MPC8610 HPCD, but that board has an ULI 1575.  The P1022Ds
doesn't.

--=20
Timur Tabi
Linux kernel developer at Freescale