VME - PowerPC: Resource sizes

Heater, Daniel (GE Infrastructure) wrote:

quoted

I don't know about x86 bus organization, but maybe it limits
the address
range for available addresses too strongly (on a single bus,
where the
Universe is on). Comparing how much window space you can map with the
old version and the new one on x86 could prove useful.

Your dead on right. I cannot allocate as much space. In fact,
on a VMIVME-7750 I'm only able to allocate 768KB now vs. the
~2MB I could access before.

Since we only request the current bus the Universe is on, there could be
a fix:
We could iterate the PCI bus tree to the top (there is some parent bus
field, IIRC), and then start complete iteration until a suitable
resource is found. This may produce larger resource regions with
reasonable effort.

Are you sure you mean 768 _KB_ and 2 _MB_, not 768 _MB_ and 2 _GB_? My
SLSI window is already 64 MB big, and with the PCI layout on my MVME2100
it is imaginable that I could map 84000000 - BEFFFFFF = 944MB (from end
of SLSI window to start of the Universe I/O memory)?

With kind regards,
Oliver Korpilla

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