From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: PMP and SEMB messages to SEP Date: Mon, 17 Jan 2011 13:55:15 -0500 Message-ID: <4D349093.6070902@garzik.org> References: <20110113192558.GE16039@MAIL.13thfloor.at> <20110114142018.GA978@htj.dyndns.org> <20110114165957.GH16039@MAIL.13thfloor.at> <20110114170407.GE978@htj.dyndns.org> <20110114173759.GI16039@MAIL.13thfloor.at> <20110117154042.GG27123@htj.dyndns.org> <1295281131.3015.44.camel@mulgrave.site> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1295281131.3015.44.camel@mulgrave.site> Sender: linux-ide-owner@vger.kernel.org To: James Bottomley Cc: Tejun Heo , Herbert Poetzl , linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org List-Id: linux-scsi@vger.kernel.org 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