On Tue, Jan 1, 2013 at 1:23 AM, Shmulik Ladkani <shmulik.ladkani@xxxxxxxxx> wrote: > Following a8ca8b64, another commit was submitted, adding similar > 'cache_op' instructions to 'mips_sc_inv' - namely 96983ffe > (MIPS: MIPSxx SC: Avoid destructive invalidation on partial L2 cachelines). > > Its purpose was to extend a8ca8b64, aligning behavior of 'mips_sc_inv' > to be similar to 'r4k_dma_cache_inv'. > > Since the explicit 'cache_op' instrcutions are now removed from > 'r4k_dma_cache_inv' (as of a16dad77), it probably makes sense to remove > them from 'mips_sc_inv' as well. > > Any reason to keep these 'cache_op's? If not, I'll submit a patch. There were a couple of USB drivers that stored DMA buffers inside a struct with other data, and invalidating the whole cacheline tended to clobber the other data. For instance, intr_buff in drivers/net/usb/pegasus.h . Does CONFIG_DMA_API_DEBUG complain if it sees unaligned start addresses or sizes? That would be a much nicer way of catching the problem, than troubleshooting random corruption.
