Date: Tue, 19 Jan 2016 14:45:23 +0300 From: Slawa Olhovchenkov <slw@zxy.spb.ru> To: "Kenneth D. Merry" <ken@FreeBSD.ORG> Cc: scsi@freebsd.org, current@freebsd.org Subject: Re: CAM Shingled Disk support patches available Message-ID: <20160119114523.GD37895@zxy.spb.ru> In-Reply-To: <20160118223704.GA87506@mithlond.kdm.org> References: <20151118171309.GA3564@mithlond.kdm.org> <20160118223704.GA87506@mithlond.kdm.org>
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On Mon, Jan 18, 2016 at 05:37:04PM -0500, Kenneth D. Merry wrote: > I have a new set of SMR patches available. See below for the full > explanation. > > The primary change here is that I have added SMR support to the ada(4) > driver. I spent some time considering whether to try to make the da(4) and > ada(4) probe infrastructure somewhat common, but in the end concluded it > would be too involved with not enough code reduction (if any) in the end. > > So, although the ideas are similar, the probe logic is separate. > > Note that NCQ support for SMR commands (Report Zones, Reset Write Pointer, > etc.) for SATA protocol shingled drives isn't active. For both the da(4) > and ada(4) driver this is for lack of a way to plumb the ATA Auxiliary > register down to the drive. > > In the ada(4) case, we need to add the register to struct ccb_ataio and > add support in one or more of the underlying SATA drivers, e.g. ahci(4). > > In the da(4) case, it will require an update of the T-10 SAT spec to > provide a way to pass the Auxiliary register down via the SCSI ATA > PASS-THROUGH command, and then a subsquent update of the SAT layer in > various vendors' SAS controller firmware. At that point, there may be > an official mapping of the SCSI ZBC commands to the ATA ZAC commands, and > we may be able to just issue the SCSI version of the commands instead of > composing ATA commands in the da(4) driver. (We'll still need to keep the > ATA passthrough version for a while at least to support controllers that > don't have the updated translation code.) Please, check me: currenly SMR lack of support in SCSI devices? On [hardvare] vendor level? Currenly only SATA controllers compatible with SMR (on command level)? (I am don't talk about FreeBSD support, question about common state).home | help
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