On 18.7.2015 18:13, Don Brace wrote: > From: shane.seymour <shane.seymour@xxxxxx> > > A regression was introduced into the hpsa driver a while back so > non-zero LUNs of multi-LUN devices may no longer be presented via > a SAS based Smart Array. I have not done a bisection to discover > the change that caused it. > > The CISS firmware specification (available on sourceforge) > defines an 8 byte lunid that describes devices that the Smart > Array can see/present to the system. The current code in the hpsa > driver attempts to find matches for non-zero LUNs with LUN 0 for > a bus/target by zeroing out byte 4 of the lunid and find a match. > > This method is sufficient for SCSI based Smart Arrays because > byte 5 is always 0. For SAS based Smart arrays byte 5 of the > lunid contains the path number for a multipath device and > either one or two bits (the documentation does not define how > many bits are used but it appears it may be one only) that > indicate if the given path number in byte 5 must always be > used to access that device. Byte 5 may not always be zero. > > The following are lunids (spaces added for clarity) for a > MSL2024 single drive library connected via a H241 Smart Array: > > 00 00 00 00 01 00 00 01 (changer) > 00 00 00 00 00 80 00 01 (tape) > > In the 4th byte (counting from 0) you can see that the tape > is LUN 0 and the changer is LUN 1. The 0x80 set in the 5th byte > for the tape drive means the driver should force access to > path 0 (the library in this case was connected to one path only > anyway). > > After the changes we can see the following in the dmesg output: > > scsi 0:3:0:0: RAID HP H241 1.18 \ > PQ: 0 ANSI: 5 > scsi 0:2:0:0: Sequential-Access HP Ultrium 6-SCSI 354W \ > PQ: 0 ANSI: 6 > scsi 0:2:0:1: Medium Changer HP MSL G3 Series 8.70 \ > PQ: 0 ANSI: 5 > > Showing that the changer is correctly identified as LUN 1 of > bus 2 target 0. Before the change the changer device is not seen. > > Suggested-by: shane.seymour <shane.seymour@xxxxxx> > Reviewed-by: Kevin Barnett <kevin.barnett@xxxxxxxx> > Reviewed-by: Scott Teel <scott.teel@xxxxxxxx> > Signed-off-by: Don Brace <don.brace@xxxxxxxx> Reviewed-by: Tomas Henzl <thenzl@xxxxxxxxxx> Tomas -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
