At Wed, 27 Jun 2012 13:41:03 +0000 (UTC), Thomas Richter wrote:
T
Hi, (please CC me on replies, not subscribed)
I recently upgraded to 3.3.6 from 2.6.33.15 (yeah, I know). Since then I noticed sometimes sounds were sometimes missing, then I noticed thousands of these in dmesg, [37280.283484] max memory size is 0x7fffffff (addr = 0x1d5d70071038000)!!
I guess you are enabling IOMMU? I guess it translates the address somehow in a way emu10k1 doesn't like. There are really little changes in emu10k1 driver itself, so if the kernel upgrade changes the behavior, it must be in the core part such like IOMMU handling.
Try to boot without iommu and see whether it changes the behavior again.
This is *not* a IOMMU configuration issue. It is an issue of where the emu10k1 allows DMA, and what the kernel does about it. If you have more than 2GB of memory, and the system runs out of 16MB ISA space, you see exactly this happening.
There is a kernel patch for this:
https://bugs.launchpad.net/ubuntu/+source/awesfx/+bug/183456
Did you see the address value in the above original report? It's the address returned from dma_alloc_coherent(). Certainly the same problem won't happen on 2GB memory system without IOMMU. It's a completely different thing.
Takashi