On Mon, Dec 19, 2005, Hans Verkuil wrote: > OK, after receiving some comments about my fix in saa7146_hlp.c I'm submitting > it again (and this time to the list first, my apologies for not doing that > before) and this time with the comment I should have added in the first place. > > I didn't just hide a warning, I actually thought about it :-) ;-) > + /* The base pointer is a 32-bit pointer into DMA memory. > + The unsigned long cast is to remove a 64-bit compile warning since > + it looks like a 64-bit address is cast to a 32-bit value. */ > + u32 base = (u32)(unsigned long)vv->ov_fb.base; For me at least, this needs more explanation. Why are these pointers 32bit even on a 64bit machine? If they are PCI addresses, then I believe there are machines who have the bus not mapped at address zero but at some offset, so you need 64 bits to represent a 32bit PCI address. (Also, shouldn't this be dma_addr_t in this case? What type does vv->ov_fb.base have?) If if is just an offset then the name is wrong. Will this value be set in a 32bit chip register? Thanks, Johannes
