Aristeu Sergio Rozanski Filho wrote: >Hi! > > >>I'm having some trouble with the DMA allocation using Linux 2.6.14-rc2 + >>some platform modifications. Namely, the dma_alloc_coherent() function >>returns bogus virtual addresses causing machine check exceptions. At >>boot, the kernel complains there is something wrong, but I cannot figure >>out how to fix it. CONFIG_CONSISTENT_START is at its default value, >>0xff100000. Any hints where to look further? >> >>Oh, this is a custom 8xx board. Has the support for DMA in 8xx been >>unstable at the time of pre-2.6.14? >> >> >probably your IMAP_ADDR is at 0xff000000, isn't it? if it is, please adjust >CONFIG_CONSISTENT_START to an address like 0xe0000000. > > > True, my IMAP_ADDR is at 0xff000000. But IMAP_SIZE is just 64 KB, so there should be no overlap, right? Or is the IMAP memory area mapped with an 8-MB TLB entry or something like that?
No badness in dma-mapping.c anymore with CONFIG_CONSISTENT_START being 0xe0000000, however. Thanks.
