[t13] T10/04-262r1

Jeff Garzik jgarzik at pobox.com
Fri Aug 13 18:26:15 PDT 2004

* From the T10 Reflector (t10 at t10.org), posted by:
* Jeff Garzik <jgarzik at pobox.com>

Doc 04-262r1 gets my vote of approval.

Major comments:

* when a SET FEATURES - XFER MODE command is issued, any bridge / OS 
driver is -STRONGLY ADVISED- to perform implementation-specific actions 
necessary to accomodate the command [such as reprogramming controller 
PIO or DMA timings]

* perhaps mention somewhere that command protocol, if specified MUST 
[using RFC language] be correct with regards to the command opcode. 
i.e. it should be a spec violation for the application to specify a READ 
DMA opcode but a PIO-In protocol.  Behavior in that case is defined as 
undefined :)

Minor comments:

* I prefer my list of command protocols, because the list is more 
abstract and transport-independent.  More "future-proof."

* similarly, if one to pursue the idea of abstraction, it would be nice 
to have three bits:  host-reset, bus-reset, and device-reset.  rather 
than HWRST.

* (regarding command protocol) "Bridges that do not implement this field 
may not be able to execute queued commands."  I would add mention of 
similar limitation in execution of vendor-reserved commands

* why separate protocols for pio-{in,out} and udma-{in,out} when you 
have a separate bit for data direction?

* in practice DMA in/out and udma in/out are the same

* is the DMA bit needed any longer?

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