On Wed, Jan 26, 2011 at 12:00:08PM -0800, David Rientjes wrote: > On Wed, 26 Jan 2011, Russell King - ARM Linux wrote: > > > On Tue, Jan 25, 2011 at 05:06:28PM -0800, David Rientjes wrote: > > > CONFIG_GENERIC_ISA_DMA and CONFIG_ISA_DMA_API usually have dependencies > > > on one another depending on the architecture and generic kernel code uses > > > either to determine whether an ISA-style DMA API is configured. > > > > Wrong. > > > > GENERIC_ISA_DMA enables support for the standard ISA DMA allocator found > > in kernel/dma.c > > > > ISA_DMA_API says that a platform supports the ISA DMA interfaces. > > > > An architecture can provide the ISA DMA interfaces, but not use the > > standard ISA DMA allocator found in kernel/dma.c. Such as the one in > > arch/arm/kernel/dma.c. > > > > So on ARM, we have platforms where ISA_DMA_API=y but GENERIC_ISA_DMA=n. > > > > Ok, fair enough. Thanks for pointing that out. I'll work to resolve the > existing dependency chain on x86 that cause build failures when one is > disabled and another is not and add Kconfig dependencies on drivers that > require GENERIC_ISA_DMA. Drivers should depend on ISA_DMA_API as that indicates that the ISA DMA API is present - in other words, when the following are available from an architecture/platform: dma_spin_lock claim_dma_lock release_dma_lock enable_dma disable_dma clear_dma_ff set_dma_mode set_dma_page set_dma_addr set_dma_count get_dma_residue request_dma free_dma GENERIC_ISA_DMA should be set by an architecture/platform when ISA_DMA_API has already been set -and- it wants to use kernel/dma.c. No drivers should depend on GENERIC_ISA_DMA. -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
