On Wed, Oct 05, 2005 at 02:21:01PM -0700, Earl Olsen wrote: > > (Sorry, I had trouble outlook and messed up the subject line) > > We are using a PPC 750 with 512m of RAM.
I dont know much about your hardware, but I'll shoot anyway. > 1) When we try to allocate memory using consistent_alloc we get a > failure with get_pteptr - there is no pte. > > 2) When we try using dma_alloc_coherent the system locks up when > we try to access that memory. > > I'm guessing these problems stem from the memory being allocated > is from the 384 bytes of RAM that gets handed over to BATs 2 AND 3, You mean Mbytes? > not the remaining memory handled by the page table. > > In the first case, pages are allocated, but since if came from the > BAT region, will not have a page table mapping. > > In the second case, if dma_alloc_init gets memory from the BAT > region, then we have the BAT and page management mechanisms > both trying to control the memory. > > Does this sound like a good theory? Has anybody encountered > this problem before? The kernel should create pte tables for all RAM, even if parts of memory are not accessed through pagetable mappings.
