On Friday 30 May 2008 03:15:57 pm Rene Herman wrote:
On 14-05-08 21:09, Rene Herman wrote:
On 14-05-08 20:50, Bjorn Helgaas wrote:
I agree, it seems a bit of a hack to use a DMA mask from the card instead of from the device, since the driver should be programming the device to do the DMA.
But I know very little about pnp_card in general, so don't attach too much weight to my opinion.
Okay, I'll sit on this for a bit. Right now we're using a global device even but this is exactly about cleaning that up so couldn't convince myself. Will see what happens when I try to make it nice...
It gets uglier. ALSA ISA drivers (for cards that exist both as legacy and as ISAPnP at least) keep a merged legacy/isapnp model; PnP is used mostly for initializing global variables that the same old legacy probe routines then reference. This means that beyond that global resource init step the specific struct device is no longer available. Without restructuring too many things really only fixable through other hacks again such as a global dma_dev[] array or some such.
From the viewpoint of PnP itself setting the dma_mask for a pnp_card (a pnp_dev collection) makes isolated sense so if no objections, I'll submit the attached after all. From the ALSA side we'd then pass the card dev (which we'd also do for isa_dev) and keep in mind that we might want to get more specific if over time structure permits it.
struct snd_pcm already has its own struct device * which would be the right one here but it's setting that which gets ugly...
Looks good to me. It does sound like a lot of work and possibly more risk than it's worth to fix up some of this stuff.
I do still wonder whether any non-x86 architectures need similar fixes in dma_alloc_coherent(), i.e., check for dev==NULL and fall back to a 24-bit DMA mask.
Acked-by: Bjorn Helgaas bjorn.helgaas@hp.com