linux/include/scsi
Alan Stern bc4f24014d [SCSI] implement runtime Power Management
This patch (as1398b) adds runtime PM support to the SCSI layer.  Only
the machanism is provided; use of it is up to the various high-level
drivers, and the patch doesn't change any of them.  Except for sg --
the patch expicitly prevents a device from being runtime-suspended
while its sg device file is open.

The implementation is simplistic.  In general, hosts and targets are
automatically suspended when all their children are asleep, but for
them the runtime-suspend code doesn't actually do anything.  (A host's
runtime PM status is propagated up the device tree, though, so a
runtime-PM-aware lower-level driver could power down the host adapter
hardware at the appropriate times.)  There are comments indicating
where a transport class might be notified or some other hooks added.

LUNs are runtime-suspended by calling the drivers' existing suspend
handlers (and likewise for runtime-resume).  Somewhat arbitrarily, the
implementation delays for 100 ms before suspending an eligible LUN.
This is because there typically are occasions during bootup when the
same device file is opened and closed several times in quick
succession.

The way this all works is that the SCSI core increments a device's
PM-usage count when it is registered.  If a high-level driver does
nothing then the device will not be eligible for runtime-suspend
because of the elevated usage count.  If a high-level driver wants to
use runtime PM then it can call scsi_autopm_put_device() in its probe
routine to decrement the usage count and scsi_autopm_get_device() in
its remove routine to restore the original count.

Hosts, targets, and LUNs are not suspended while they are being probed
or removed, or while the error handler is running.  In fact, a fairly
large part of the patch consists of code to make sure that things
aren't suspended at such times.

[jejb: fix up compile issues in PM config variations]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
2010-07-28 09:07:50 -05:00
..
fc [SCSI] libfcoe: add protocol description of FIP VN2VN mode 2010-07-28 09:05:55 -05:00
fc_encode.h [SCSI] libfc: add fc_fill_reply_hdr() and fc_fill_hdr() 2010-07-28 09:06:00 -05:00
fc_frame.h [SCSI] libfc: add fc_frame_sid() and fc_frame_did() functions 2010-07-28 09:05:59 -05:00
iscsi_if.h [SCSI] iscsi_transport: added new iscsi_param to display target alias in sysfs 2010-07-28 09:05:25 -05:00
iscsi_proto.h [SCSI] libiscsi: Check TMF state before sending PDU 2009-12-04 12:01:36 -06:00
Kbuild [SCSI] Unexport scsi/scsi.h from headers_install 2010-05-02 11:45:12 -04:00
libfc.h [SCSI] libfc: don't require a local exchange for incoming requests 2010-07-28 09:06:02 -05:00
libfcoe.h [SCSI] libfcoe: fcoe: fnic: add FIP VN2VN point-to-multipoint support 2010-07-28 09:05:56 -05:00
libiscsi_tcp.h kfifo: move struct kfifo in place 2009-12-22 14:17:55 -08:00
libiscsi.h [SCSI] libiscsi: Make iscsi_eh_target_reset start with session reset 2010-03-03 17:39:04 +05:30
libsas.h [SCSI] Unify SAM_ and SAM_STAT_ macros 2010-07-28 09:07:49 -05:00
libsrp.h libsrp: fix compile failure 2009-12-30 12:23:27 -08:00
osd_attributes.h [SCSI] libosd: OSD2r05: Attribute definitions 2009-06-10 08:54:07 -05:00
osd_initiator.h [SCSI] libosd: Fix blk_put_request locking again 2009-12-10 08:54:17 -06:00
osd_protocol.h [SCSI] osd_protocol.h: Add missing #include 2009-12-04 12:01:48 -06:00
osd_sec.h [SCSI] libosd: OSDv1 Headers 2009-03-12 12:58:06 -05:00
osd_sense.h [SCSI] libosd: osd_sense: OSD_CFO_PERMISSIONS 2009-12-04 12:01:44 -06:00
osd_types.h [SCSI] libosd: OSDv1 Headers 2009-03-12 12:58:06 -05:00
sas_ata.h [SCSI] libsas: fix missing inlines in header file 2008-04-07 12:19:10 -05:00
sas.h [SCSI] libsas: Convert sas_proto users to sas_protocol 2008-01-11 18:22:41 -06:00
scsi_bsg_fc.h [SCSI] fc-transport: Use packed modifier for fc_bsg_request structure. 2010-01-17 12:36:33 -06:00
scsi_cmnd.h [SCSI] Deprecate SCSI_PROT_*_CONVERT operations 2009-10-02 09:46:25 -05:00
scsi_dbg.h [SCSI] Fix device not ready printk 2007-10-12 14:51:56 -04:00
scsi_device.h [SCSI] implement runtime Power Management 2010-07-28 09:07:50 -05:00
scsi_devinfo.h
scsi_dh.h [SCSI] scsi_dh: Change the scsidh_activate interface to be asynchronous 2009-12-04 12:00:46 -06:00
scsi_driver.h sd, sr: fix Driver 'sd' needs updating message 2009-06-21 12:01:27 -05:00
scsi_eh.h [SCSI] scsi_eh_prep_cmnd should save scmd->underflow 2008-07-26 15:14:56 -04:00
scsi_host.h SCSI: implement sd_unlock_native_capacity() 2010-06-02 13:50:04 -04:00
scsi_ioctl.h [PATCH] don't mess with file in scsi_nonblockable_ioctl() 2008-10-21 07:47:28 -04:00
scsi_netlink_fc.h [SCSI] SCSI & FC transport: extend event vendor id's to 64bits 2006-09-02 15:35:15 -05:00
scsi_netlink.h [SCSI] scsi_netlink: Add transport and LLD recieve and event support 2008-10-03 11:46:13 -05:00
scsi_scan.h PM/Hibernate: Wait for SCSI devices scan to complete during resume 2009-04-13 11:37:07 -07:00
scsi_tcq.h scsi: make sure that scsi_init_shared_tag_map() doesn't overwrite existing map 2008-10-27 19:25:30 +01:00
scsi_tgt_if.h [SCSI] tgt: add I_T nexus support 2007-10-12 14:37:50 -04:00
scsi_tgt.h [SCSI] tgt: add I_T nexus support 2007-10-12 14:37:50 -04:00
scsi_transport_fc.h [SCSI] Allow FC LLD to fast-fail scsi eh by introducing new eh return 2010-04-11 09:49:33 -05:00
scsi_transport_iscsi.h [SCSI] iscsi_transport: wait on session in error handler path 2010-07-28 09:06:06 -05:00
scsi_transport_sas.h [SCSI] scsi_transport_sas: add support for transport layer retries (TLR) 2010-02-08 17:15:19 -06:00
scsi_transport_spi.h [SCSI] aic79xx: make driver respect nvram for IU and QAS settings 2009-06-15 10:09:35 -05:00
scsi_transport_srp.h [SCSI] tgt: move tsk_mgmt_response callback to transport class 2007-10-12 14:38:01 -04:00
scsi_transport.h block: unify request timeout handling 2008-10-09 08:56:13 +02:00
scsi.h [SCSI] Add missing scsi command definitions 2010-04-30 12:46:17 -05:00
scsicam.h
sg.h sysctl extern cleanup: sg 2010-03-12 15:53:10 -08:00
srp.h [SCSI] srp.h: Add I/O Class values 2006-06-17 20:37:38 -07:00