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+What: /sys/class/sas_phy/phy-<host>:<phy identifier>,
+ phy-<host>:<scsi target id>:<phy identifier>
+Date: Nov, 2018
+KernelVersion: 2.6.13
+Contact: linux-scsi@vger.kernel.org
+Description: SAS PHY entry directory, which includes interfaces to control
+ the PHY, physical layer information on the PHY, and other SAS
+ fabric management information asscoiated with the PHY.
+
+What: /sys/class/sas_port/port-<host>:<port identifier>,
+ port-<host>:<scsi target id>:<port identifier>
+Date: Nov, 2018
+KernelVersion: 2.6.13
+Contact: linux-scsi@vger.kernel.org
+Description: SAS Port entry directory, with constituient PHY count and
+ other SAS fabric management information asscoiated with the
+ Port.
+
+
+
+
The SAS transport class ABI is currently undocumented. Some systemd issues have been raised for SAS device support [1], [2]. Because of this, distros using systemd may have broken symlinks, like /dev/disk/by-path Unfortunately it is challenging to support SAS devices as the ABI is not well documented and is not always intuitive, so add a stable ABI definition. [1] https://github.com/systemd/systemd/issues/3943#issuecomment-240982482 [2] https://github.com/systemd/systemd/issues/7157 Signed-off-by: John Garry <john.garry@huawei.com> -- I am sending this as an incomplete RFC to ensure it's the right thing to do, so I don't bother writing the document to find it later rejected. For now, this is just a minimal effort. -- 1.9.1