svn commit: r238172 - head/sys/dev/agp

[John Baldwin]

On Saturday, July 07, 2012 10:44:14 am Marcel Moolenaar wrote:
> The commit log states the motivation: developers tend to copy-n-paste without
> truly understanding the subtle differences and may use the Maxmem use in
> agp_i810.c as the wrong precedence. Secondly, also mentioned in the commit
> log, is the use of realmem in agp.c and then Maxmem in agp_i810.c which is
> likely to be confusing. So the change from Maxmem to realmem in agp_i810.c
> prioritizes the avoidance of confusion over pedantic correctness, which we
> all know isn't achievable anyway. Since agp_i810.c is only for amd64, i386
> and pc98, also stated in the commit log, and all of those have dense phys.
> memory, the discrepancy is still within the margin of error.

1GB is a rather large margin IMO.  If agp_i810.c actually cares about the
maximum PA and not the size of RAM, then it should use the correct variable
for this purpose.  The copy-n-paste thing works both ways.  You don't want
someone to use realmem instead of Maxmem elsewhere because they copy-n-paste
the wrong thing from agp_i810.c.  I think the solution is to fix things to
use what the actually need.  In the case of agp_i810.c it sounds like that is
Maxmem.

-- 
John Baldwin