On 01/17/2011 11:18 AM, James Bottomley wrote:
On Mon, 2011-01-17 at 16:40 +0100, Tejun Heo wrote:
- the SiI3726 supports GPIO pins, which can be reached via
the General Status and Control Register [130] and accoring
to the docu, the Read/Write Port Multiplier command can
be used to read/write that register.
+ how would I go about issuing such a command and where
should it be done? i.e. what about interference with
other commands? what about retrieving return values?
The problem is that the PMP device itself is currently not allocated a
userland visible device, so it doesn't have any /dev/* node. Hmmm...
So perhaps it should be. If you look at the equivalent topology on SAS,
our expanders have a bsg device node precisely so that we can do this.
That said, SAS expanders have a defined protocol (SAS Management
Protocol) to talk to the outside world, so they are real visible objects
always in our topology ... I'm not sure PMP has this ... it seems that
all PMP visibility is an extension to the standard?
Yes, we do need a way to address these devices.
Jeff
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