On Sun, 22 Jul 2007 18:42:14 +0800 jidong xiao wrote:
> Any one can kindly explain this?
>
> Thanks
> Jason Xiao
>
> On 7/21/07, jidong xiao <jidong.xiao@xxxxxxxxx> wrote:
> > I noticed that there is a char scsi_level in the struct scsi_device,
> > what does scsi_level mean?
> >
> > struct scsi_device {
> > ...
> > char scsi_level;
> > ...
> > }
Does this help?
It's explained in include/scsi/scsi.h as:
/*
* struct scsi_device::scsi_level values. For SCSI devices other than those
* prior to SCSI-2 (i.e. over 12 years old) this value is (resp[2] + 1)
* where "resp" is a byte array of the response to an INQUIRY. The scsi_level
* variable is visible to the user via sysfs.
*/
#define SCSI_UNKNOWN 0
#define SCSI_1 1
#define SCSI_1_CCS 2
#define SCSI_2 3
#define SCSI_3 4 /* SPC */
#define SCSI_SPC_2 5
#define SCSI_SPC_3 6
> > Is it SCSI revision?
> > If the answer is true, then I am quite curious, from the code I have
> > read, SCSI_2 is something special, see following function:
> > picked up from drivers/scsi/scsi_sysfs.c:
> > int scsi_sysfs_target_initialize(struct scsi_device *sdev){
> > /*
> > * If there wasn't another lun already configured at
> > * this target, then default this device to SCSI_2
> > * until we know better
> > */
> > sdev->scsi_level = SCSI_2;
> > }
> >
> > Why SCSI_2 could be the default value, why not SCSI_1, why not SCSI_3,
> > and etc.Seems SCSI_2 is distinguished from other levels,any reason for
> > this?
> >
> > Thanks
> > Jason Xiao
---
~Randy
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