> > * John Keller [2008-11-17 10:24]: > > > > Create a platform specific version of dma_get_required_mask() > > for ia64 SN Altix. All SN Altix platforms support 64 bit DMA > > addressing regardless of the size of system memory. > > Create a ia64 machvec for dma_get_required_mask, with the > > SN version unconditionally returning DMA_64BIT_MASK. > > Maybe we should then switch the ia64_platform_is("sn2") > in check_crashkernel_memory() to dma_get_required_mask() == > DMA_64BIT_MASK because that's basically what the check is about. > > BTW: What about UV? > > > Regards, > Bernhard > -- > Bernhard Walle, SUSE Linux Products GmbH, Architecture Development > This patch addresses a problem on SN Altix systems with < 4GB, where device drivers using the dma_get_required_mask() API would be told to use 32 bit DMA, when 64 bit is more efficient. How exactly the use of dma_get_required_mask() relates to the crash kernel code you refer to is unclear to me. If, for all platforms, the crash kernel code could use the mask returned from dma_get_required_mask() to do its check, then switching the code might be OK. But, if that's not possible for some platforms, then I'd wonder if dma_get_required_mask() is being used in the wrong context in this case. For UV systems, the default/generic dma_get_required_mask() will be used, returning a value based on the size of system memory. John -- To unsubscribe from this list: send the line "unsubscribe linux-ia64" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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