Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override

From: H. Peter Anvin
Date: Mon Dec 31 2007 - 18:43:33 EST


Alan Cox wrote:
However, assuming a bus clock of 6 MHz should be safe (167 ns).

Agreed - or ISA timings directly. Boxes using WD80x3 are not going to
have a TSC so might as well stick with port 0x80 as they have done just
fine for the past 15 years.

None of this really helps with *memory-mapped* 8390, though, since memory mapped writes can be posted. Putting any IOIO transaction in the

ISA isn't posted only PCI.

PCI 8390 clones seem to be a mix of ASICs and 8390x chips with
some quite disgusting FPGA glue logic.


ISA isn't posted no, but on several chipsets the upstream PCI bus will post MMIO writes to ISA space regardless of the spec.

-hpa
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