On Tue, 2008-08-05 at 14:40 +0200, Martin Petermann wrote: > With kernel 2.6.19 a change was introduced that no sg device was > generated if PQ=1, PDT=0x1f was returned from the particular device: > > commit 84961f28e9d13a4b193d0c8545f3c060c1890ff3 > Author: dave wysochanski <davidw@xxxxxxxxxx> > Date: Wed Aug 9 14:56:32 2006 -0400 > > [SCSI] Don't add scsi_device for devices that return PQ=1, PDT=0x1f > > Before it was possible on Linux 390 in user space to a e.g. LUN 0 to a > port and to receive a generic device: > > t6345056:/sys/bus/ccw/devices/0.0.5922/0x500507630313c562 # ll > total 0 > -r--r--r-- 1 root root 4096 Aug 4 12:07 access_denied > -rw-r--r-- 1 root root 4096 Aug 4 12:07 failed > -r--r--r-- 1 root root 4096 Aug 4 12:07 in_recovery > -r--r--r-- 1 root root 4096 Aug 4 12:07 status > --w------- 1 root root 4096 Aug 4 12:07 uevent > --w------- 1 root root 0 Aug 4 13:46 unit_add > --w------- 1 root root 0 Aug 5 14:24 unit_remove > t6345056:/sys/bus/ccw/devices/0.0.5922/0x500507630313c562 # echo 0 > > unit_add > t6345056:/sys/bus/ccw/devices/0.0.5922/0x500507630313c562 # ll > total 0 > drwxr-xr-x 2 root root 0 Aug 5 14:25 0x0000000000000000 > -r--r--r-- 1 root root 4096 Aug 4 12:07 access_denied > -rw-r--r-- 1 root root 4096 Aug 4 12:07 failed > -r--r--r-- 1 root root 4096 Aug 4 12:07 in_recovery > -r--r--r-- 1 root root 4096 Aug 4 12:07 status > --w------- 1 root root 4096 Aug 4 12:07 uevent > --w------- 1 root root 0 Aug 5 14:25 unit_add > --w------- 1 root root 0 Aug 5 14:24 unit_remove > t6345056:/sys/bus/ccw/devices/0.0.5922/0x500507630313c562 # lsscsi -g > [0:0:0:0] no dev IBM 2107900 2.27 - /dev/sg0 > > After this fix there is no /dev/sg0 device generated. > > We are utilizing the possibility to create such a device for the > sg_utils commands in the case no other LUN has been attached to a port. > > I do not want to put this fix into question. I would like to know if > someone has an idea how to workaround this problem and to generate a > generic device in user space using kernel 2.6.19 or a later version. First of all, why is the device returning PQ=1 PTD=0x1f? this should mean its not connected and probably doesn't exist... ie inaccessible without some unspecified action being taken. If you can use it, it's clearly not behaving like a PQ=1 LUN. Perhaps the simplest thing would be for something in s390 to fix up the inquiry data ... or we could allow you could have a script to force it to appear (as in if you send a specific scan for this one LUN we could override the catch in the code that throws it out again). James -- 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
