On Tue, Nov 15, 2011 at 2:33 AM, Raffaele BELARDI <raffaele.bela...@st.com> wrote: > I have two gentoo boxes, X has an ASUS M2NPV-VM with AMD64 3500+ CPU, Y > has a AMD64 X2 5600+ CPU. Since I need more juice on X I thought I could > swap CPUs. > > After updating X's BIOS the system with the 'new' CPU boots up to the > MythTv screen with no error but does not respond to the USB keyboard nor > to the remote control keypresses. More precisely: > > - keyboard is fine at grub boot, I can select up and down or edit the > entries > - keyboard is no longer responsive at the init scripts start (when you > can press 'I' to select services) > > My first thought was that X (and Y) WERE compiled with '-march=native' > GCC flag and maybe the 5600+ does not execute properly the 3500+ code. > But a quick search on wikipedia shows that 5600+ has a superset of the > 3500+ so I should have problems putting the 3500+ in the Y box, not > vice-versa. > > Any suggestions?
Play with your BIOS settings. Look for things like legacy USB support. Also, double-check that all the relevant USB drivers (UHCI, EHCI, XHCI, HID, etc) are either built-into the kernel, or are loaded as modules. Consider rebuilding your kernel. Just because one processor has a superset of the instructions of the other doesn't mean there may not be other compatibilities. Some time back, a thread on here discussed how to find out what -march=native becomes, in terms of -march and a bunch of other parameters. I've noticed parameters like cache line sizes and cache sizes, among a couple others. I imagine a bungling of, e.g., cache line sizes could break code that has heavy dependency on data locality and/or memory models; it might have broken your USB drivers, for example. But, really, I think BIOS settings and driver presence are the more likely culprit. -- :wq
