--- scsi_mid_low_api.txt 2003-05-05 14:03:22.000000000 +1000 +++ scsi_mid_low_api.txt030429 2003-04-29 09:34:05.000000000 +1000 @@ -22,7 +22,10 @@ a SCSI host and a PCI device is common but not required (e.g. with ISA or MCA adapters).] -This version of the document roughly matches linux kernel version 2.5.67 . +This version of the document roughly matches linux kernel version 2.5.68 . +This document can be found in the Linux kernel source Documentation/scsi +directory and is called scsi_mid_low_api.txt . A more recent copy may +be found at http://www.torque.net/scsi/scsi_mid_low_api.txt.gz . Documentation ============= @@ -142,13 +145,14 @@ slave_configure() --> scsi_adjust_queue_depth() | slave_alloc() - slave_configure() --> scsi_adjust_queue_depth() + slave_configure() | slave_alloc() ** slave_destroy() ** -The invocation of scsi_adjust_queue_depth() by the LLD is required -if slave_configure() is supplied. +If the LLD wants to adjust the default queue settings, it can invoke +scsi_adjust_queue_depth() in its slave_configure() routine. + ** For scsi devices that the mid level tries to scan but do not respond, a slave_alloc(), slave_destroy() pair is called. @@ -179,7 +183,7 @@ scsi_add_device() ------+ | slave_alloc() - slave_configure() --> scsi_adjust_queue_depth() + slave_configure() [--> scsi_adjust_queue_depth()] [DEVICE unplug] LLD mid level LLD @@ -228,13 +232,14 @@ slave_destroy() ** | slave_alloc() - slave_configure() --> scsi_adjust_queue_depth() + slave_configure() slave_alloc() ** slave_destroy() ** -If the LLD does not supply a slave_configure() then the mid level invokes -scsi_adjust_queue_depth() itself with tagged queuing off and "cmd_per_lun" -for that host as the queue length. +The mid level invokes scsi_adjust_queue_depth() with tagged queuing off and +"cmd_per_lun" for that host as the queue length. These settings can be +overridden by a slave_configure() supplied by the LLD. + ** For scsi devices that the mid level tries to scan but do not respond, a slave_alloc(), slave_destroy() pair is called. @@ -1093,11 +1098,6 @@ * Notes: Allows the driver to inspect the response to the initial * INQUIRY done by the scanning code and take appropriate action. * For more details see the hosts.h file. - * If this function is not supplied, the mid level will call - * scsi_adjust_queue_depth() with the struct Scsi_Host::cmd_per_lun - * value on behalf of the given device. If this function is - * supplied then its implementation must call - * scsi_adjust_queue_depth(). * * Defined in: LLD **/ @@ -1277,8 +1277,9 @@ Patrick Mansfield Christoph Hellwig Doug Ledford + Andries Brouwer Douglas Gilbert dgilbert@interlog.com -19th April 2003 +29th April 2003