On Sat, 9 Nov 2024, Magnus Lindholm wrote: > What's your thoughts on his approach: > > if (card is ISP1040 and revision less than C) then use > dma_get_required_mask() > else > do as before > > Assuming dma_get_required_mask() works it should return a > 64-something-bit mask on IP30/MIPS but only 32-bits on Alpha. It's not required for the mask returned by dma_get_required_mask() to be 32-bit, so unless your card does support DAC (and everything so far shows it does not), it will still fail on another platform where the function does return a mask beyond 32 bits. Are you able to verify your card with a non-Alpha system that has memory beyond the low 32-bit DMA space? I guess not, or you'd have done that already, wouldn't you? If you really wanted to double-check your Alpha correctly supports DAC, you could try wiring your ISP1080 device temporarily via a 32-bit PCI riser adapter (or an external 32-bit PCI enclosure) so as to force 64-bit addressing via AD[31:0] lines only (assuming that ISP1080 got DAC support right though). Maciej
