On Wed, 9 Oct 2002, Nate Lawson wrote: > On Wed, 9 Oct 2002, Andrew Gallatin wrote: > > ... > > Clashing with int nsegments: > > > > Sparc64 has the same problem. ia64 gets around it by just making > > BUS_SPACE_UNRESTRICTED an int: > > > > #define BUS_SPACE_UNRESTRICTED (~0) > > > > I'd like to do the same for alpha. I think this is valid, as > > BUS_SPACE_UNRESTRICTED seems to be used exlusively as an argument > > to bus_dma_tag_create(... nsegments = BUS_SPACE_UNRESTRICTED...) > > Yes, I looked into this before and agree this is a valid approach. It's > likely the number of segments never exceeds 32, let alone 2^31.
However, it is likely that the number of segments exeeds ~0 (which is -1 on normal 2's complement machines). bus_dma_tag_create() has a bogus interface. It takes an "int nsegments" arg but corrupts it immediately to a "u_int nsegments" struct member. BUS_SPACE_UNRESTRICTED seems to be used as a generic (null) limit in at least the isp driver. It is not clear that ~0 has the correct overflow and sign extension behaviour for this. ~0UL works better as a generic limit. It even points to the bogus interface. Bruce To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-current" in the body of the message
