Raj, Ashok writes:
> it works for now, since the addr msb's are 0. but if this physical addr is a
> true 64bit addr
> the above wont work..
On a 32-bit system, the BIOS (nor the kernel) will never assign a
resource to the device with the upper 32-bits non-zero.
This is also done for compatability reasons, so that PCI devices which
may only perform SAC transactions (ie. no dual-address cycle
capability) may do PCI peer-to-peer DMA to/from devices even when
using 64-bit BARs.
To be honest, 64-bit BARs are pretty useless today, being that %99 of
PCI controllers do not even provide a way for the cpu to address the
PCI memory space above 4GB. This is true even on 64-bit CPU systems.
In short there are no problems.
David S. Miller
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to email@example.com
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Mon Jul 23 2001 - 21:00:14 EST