[ugly patch] Save .15W-.5W by AHCI powersaving

From: Pavel Machek
Date: Mon Feb 25 2008 - 08:46:00 EST

Hi!

This is a patch (very ugly, assumes you have just one disk) to bring
powersaving to AHCI. You need Alan's SCSI autosuspend (attached) patch
as a base.

It saves .5W compared to config with disk spinning, and even .15W
compared to hdparm -y... on my thinkpad x60 anyway.

It is also mandatory first step towards sleepy linux ;-).

Pavel
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index 29e71bd..0197b1f 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -259,8 +260,8 @@ static void ahci_fill_cmd_slot(struct ah
u32 opts);
#ifdef CONFIG_PM
static int ahci_port_suspend(struct ata_port *ap, pm_message_t mesg);
-static int ahci_pci_device_suspend(struct pci_dev *pdev, pm_message_t mesg);
-static int ahci_pci_device_resume(struct pci_dev *pdev);
+int ahci_pci_device_suspend(struct pci_dev *pdev, pm_message_t mesg);
+int ahci_pci_device_resume(struct pci_dev *pdev);
#endif

static struct class_device_attribute *ahci_shost_attrs[] = {
@@ -268,6 +269,35 @@ static struct class_device_attribute *ah
NULL
};

+struct pci_dev *my_pdev;
+int autosuspend_enabled;
+
+/* The host and its devices are all idle so we can autosuspend */
+static int autosuspend(struct Scsi_Host *host)
+{
+ if (my_pdev && autosuspend_enabled) {
+ printk("ahci: should autosuspend\n");
+ ahci_pci_device_suspend(my_pdev, PMSG_SUSPEND);
+ return 0;
+ }
+ printk("ahci: autosuspend disabled\n");
+ return -EINVAL;
+}
+
+/* The host needs to be autoresumed */
+static int autoresume(struct Scsi_Host *host)
+{
+ if (my_pdev && autosuspend_enabled) {
+ printk("ahci: should autoresume\n");
+ ahci_pci_device_resume(my_pdev);
+ return 0;
+ }
+ printk("ahci: autoresume disabled\n");
+ return -EINVAL;
+}
+
+
+
static struct scsi_host_template ahci_sht = {
.module = THIS_MODULE,
.name = DRV_NAME,
@@ -286,6 +322,8 @@ static struct scsi_host_template ahci_sh
.slave_destroy = ata_scsi_slave_destroy,
.bios_param = ata_std_bios_param,
.shost_attrs = ahci_shost_attrs,
+ .autosuspend = autosuspend,
+ .autoresume = autoresume,
};

static const struct ata_port_operations ahci_ops = {
@@ -2300,8 +2356,12 @@ static int ahci_init_one(struct pci_dev
ahci_print_info(host);

pci_set_master(pdev);
- return ata_host_activate(host, pdev->irq, ahci_interrupt, IRQF_SHARED,
+
+ rc = ata_host_activate(host, pdev->irq, ahci_interrupt, IRQF_SHARED,
&ahci_sht);
+ pci_save_state(pdev);
+ my_pdev = pdev;
+ return rc;
}

static int __init ahci_init(void)
diff --git a/drivers/ata/libata-eh.c b/drivers/ata/libata-eh.c
index 4e31071..5c40ac2 100644
--- a/drivers/ata/libata-eh.c
+++ b/drivers/ata/libata-eh.c
@@ -380,7 +381,7 @@ enum scsi_eh_timer_return ata_scsi_timed
* Inherited from SCSI layer (none, can sleep)
*
* RETURNS:
- * Zero.
+ * Nothing.
*/
void ata_scsi_error(struct Scsi_Host *host)
{
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index c838e65..0edc25e 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -484,6 +484,8 @@ static int scsi_try_host_reset(struct sc
if (scsi_autoresume_host(shost) != 0)
return FAILED;

+ rtn = shost->hostt->eh_host_reset_handler(scmd);
+
if (rtn == SUCCESS) {
if (!shost->hostt->skip_settle_delay)
ssleep(HOST_RESET_SETTLE_TIME);
@@ -1577,7 +1579,11 @@ int scsi_error_handler(void *data)
* what we need to do to get it up and online again (if we can).
* If we fail, we end up taking the thing offline.
*/
+#if 0
+ /* libata uses scsi_error_handler to suspend its parts; we deadlock
+ if we try to autoresume here */
autoresume_rc = scsi_autoresume_host(shost);
+#endif
if (shost->transportt->eh_strategy_handler)
shost->transportt->eh_strategy_handler(shost);
else
@@ -1591,8 +1597,10 @@ int scsi_error_handler(void *data)
* which are still online.
*/
scsi_restart_operations(shost);
+#if 0
if (autoresume_rc == 0)
scsi_autosuspend_host(shost);
+#endif
set_current_state(TASK_INTERRUPTIBLE);
}
__set_current_state(TASK_RUNNING);
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 233feee..3c598e0 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -67,6 +67,8 @@ #undef SP

static struct kmem_cache *scsi_bidi_sdb_cache;

+void scsi_run_queue(struct request_queue *q);
+
/*
* Function: scsi_unprep_request()
*
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 5393e15..25bebc1 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -340,6 +340,21 @@ static int scsi_bus_uevent(struct device
return 0;
}

+static int scsi_bus_remove(struct device *dev)
+{
+ struct device_driver *drv = dev->driver;
+ struct scsi_device *sdev = to_scsi_device(dev);
+ int err = 0;
+
+ /* reset the prep_fn back to the default since the
+ * driver may have altered it and it's being removed */
+ blk_queue_prep_rq(sdev->request_queue, scsi_prep_fn);
+
+ if (drv && drv->remove)
+ err = drv->remove(dev);
+
+ return 0;
+}

struct bus_type scsi_bus_type = {
.name = "scsi",
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 16add9a..9ca12d1 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -1596,6 +1596,8 @@ static int sd_revalidate_disk(struct gen
return 0;
}

+struct device *my_scsi_disk;
+
/**
* sd_probe - called during driver initialization and whenever a
* new scsi device is attached to the system. It is called once
@@ -1715,6 +1717,7 @@ static int sd_probe(struct device *dev)

scsi_use_ULD_pm(sdp, 1);
scsi_autosuspend_device(sdp);
+ my_scsi_disk = dev;
return 0;

out_suspend:
@@ -1835,6 +1838,8 @@ static int sd_suspend(struct device *dev
struct scsi_disk *sdkp = scsi_disk_get_from_dev(dev);
int ret = 0;

+ printk("sleepy: sd_suspend start\n");
+
if (!sdkp)
return 0; /* this can happen */




--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>

Alan Stern's autosuspend-for-SCSI patches.

---
commit 8b534a6dc550b4115627e35535f07753d5612800
tree a8e2b2eafb680fb8c5c5bcad049d29f23f576b43
parent 9c269a8b0695a4b18d36b918cb14b757f73e6a49
author Pavel <pavel@xxxxxxxxxx> Mon, 25 Feb 2008 13:43:18 +0100
committer Pavel <pavel@xxxxxxxxxx> Mon, 25 Feb 2008 13:43:18 +0100

Documentation/scsi/scsi_mid_low_api.txt | 50 ++++++++++++++++++++++++++++
drivers/scsi/Kconfig | 12 +++++++
drivers/scsi/Makefile | 3 +-
drivers/scsi/hosts.c | 20 ++++-------
drivers/scsi/scsi.c | 8 ++++
drivers/scsi/scsi_error.c | 36 +++++++++++++-------
drivers/scsi/scsi_lib.c | 7 ++--
drivers/scsi/scsi_priv.h | 38 +++++++++++++++++++++
drivers/scsi/scsi_scan.c | 9 +++++
drivers/scsi/scsi_sysfs.c | 56 ++++---------------------------
drivers/scsi/sd.c | 12 ++++++-
drivers/scsi/sg.c | 10 ++++++
drivers/usb/storage/scsiglue.c | 35 +++++++++++++++++--
drivers/usb/storage/usb.c | 15 ++++----
include/scsi/scsi_device.h | 23 ++++++++++++-
include/scsi/scsi_host.h | 24 +++++++++++++
16 files changed, 264 insertions(+), 94 deletions(-)

diff --git a/Documentation/scsi/scsi_mid_low_api.txt b/Documentation/scsi/scsi_mid_low_api.txt
index a6d5354..98dc005 100644
--- a/Documentation/scsi/scsi_mid_low_api.txt
+++ b/Documentation/scsi/scsi_mid_low_api.txt
@@ -782,6 +782,8 @@ In some cases more detail is given in sc
The interface functions are listed below in alphabetical order.

Summary:
+ autoresume - perform dynamic (runtime) host resume
+ autosuspend - perform dynamic (runtime) host suspend
bios_param - fetch head, sector, cylinder info for a disk
detect - detects HBAs this driver wants to control
eh_timed_out - notify the host that a command timer expired
@@ -802,6 +804,54 @@ Summary:
Details:

/**
+ * autoresume - perform dynamic (runtime) host resume
+ * @shp: host to resume
+ *
+ * Resume (return to an operational power level) the specified host.
+ * Return 0 if the resume was successful, otherwise a negative
+ * error code.
+ *
+ * Locks: struct Scsi_Host::pm_mutex held throughout the call.
+ *
+ * Calling context: process
+ *
+ * Notes: If the host is not currently suspended, this method does
+ * need to do anything.
+ *
+ * Optionally defined in: LLD
+ **/
+ int autoresume(struct Scsi_Host *shp)
+
+
+/**
+ * autosuspend - perform dynamic (runtime) host suspend
+ * @shp: host to suspend
+ *
+ * Suspend (change to a non-operational low-power state) the
+ * specified host.
+ * Return 0 if the suspend was successful (or was successfully
+ * queued, or was successfully ignored), otherwise a negative
+ * error code.
+ *
+ * Locks: struct Scsi_Host::pm_mutex held throughout the call.
+ *
+ * Calling context: process
+ *
+ * Notes: The suspend need not be carried out immediately (or indeed
+ * at all); it may be delayed indefinitely. The real meaning of this
+ * method call is that all of the host's devices are now idle. It can
+ * happen that an autosuspend is quickly followed by an autoresume,
+ * so it is beneficial if the suspend is delayed by a few seconds.
+ * A host is assumed to be at full power (resumed) when it is
+ * first created. In the absence of errors, the LLD will receive a
+ * strictly alternating sequence of autosuspend, autoresume,... calls.
+ *
+ * Optionally defined in: LLD
+ **/
+ int autosuspend(struct Scsi_Host *shp)
+
+
+/**
* bios_param - fetch head, sector, cylinder info for a disk
* @sdev: pointer to scsi device context (defined in
* include/scsi/scsi_device.h)
diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig
index a7a0813..9bada81 100644
--- a/drivers/scsi/Kconfig
+++ b/drivers/scsi/Kconfig
@@ -57,6 +57,18 @@ config SCSI_PROC_FS

If unsure say Y.

+config SCSI_DYNAMIC_PM
+ bool "SCSI dynamic Power Management support (EXPERIMENTAL)"
+ depends on SCSI && PM && EXPERIMENTAL
+ ---help---
+ This option enables support for dynamic (or runtime)
+ power management of SCSI devices and host adapters.
+ If you say Y here, you can use the sysfs "power/level"
+ and "power/autosuspend" files to control manual or
+ automatic suspend/resume of individual SCSI devices.
+
+ If unsure say N.
+
comment "SCSI support type (disk, tape, CD-ROM)"
depends on SCSI

diff --git a/drivers/scsi/Makefile b/drivers/scsi/Makefile
index 925c26b..634a0e4 100644
--- a/drivers/scsi/Makefile
+++ b/drivers/scsi/Makefile
@@ -139,7 +139,8 @@ obj-$(CONFIG_SCSI_WAIT_SCAN) += scsi_wai
scsi_mod-y += scsi.o hosts.o scsi_ioctl.o constants.o \
scsicam.o scsi_error.o scsi_lib.o
scsi_mod-$(CONFIG_SCSI_DMA) += scsi_lib_dma.o
-scsi_mod-y += scsi_scan.o scsi_sysfs.o scsi_devinfo.o
+scsi_mod-y += scsi_scan.o scsi_sysfs.o scsi_devinfo.o \
+ scsi_pm.o
scsi_mod-$(CONFIG_SCSI_NETLINK) += scsi_netlink.o
scsi_mod-$(CONFIG_SYSCTL) += scsi_sysctl.o
scsi_mod-$(CONFIG_SCSI_PROC_FS) += scsi_proc.o
diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index 880c78b..250cdab 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -154,24 +154,15 @@ EXPORT_SYMBOL(scsi_host_set_state);
**/
void scsi_remove_host(struct Scsi_Host *shost)
{
- unsigned long flags;
- mutex_lock(&shost->scan_mutex);
- spin_lock_irqsave(shost->host_lock, flags);
- if (scsi_host_set_state(shost, SHOST_CANCEL))
- if (scsi_host_set_state(shost, SHOST_CANCEL_RECOVERY)) {
- spin_unlock_irqrestore(shost->host_lock, flags);
- mutex_unlock(&shost->scan_mutex);
- return;
- }
- spin_unlock_irqrestore(shost->host_lock, flags);
- mutex_unlock(&shost->scan_mutex);
+ if (scsi_pm_host_stop(shost))
+ return;
scsi_forget_host(shost);
scsi_proc_host_rm(shost);

- spin_lock_irqsave(shost->host_lock, flags);
+ spin_lock_irq(shost->host_lock);
if (scsi_host_set_state(shost, SHOST_DEL))
BUG_ON(scsi_host_set_state(shost, SHOST_DEL_RECOVERY));
- spin_unlock_irqrestore(shost->host_lock, flags);
+ spin_unlock_irq(shost->host_lock);

transport_unregister_device(&shost->shost_gendev);
class_device_unregister(&shost->shost_classdev);
@@ -236,6 +227,7 @@ int scsi_add_host(struct Scsi_Host *shos
if (error)
goto out_destroy_host;

+ scsi_autosuspend_host(shost);
scsi_proc_host_add(shost);
return error;

@@ -386,6 +378,8 @@ struct Scsi_Host *scsi_host_alloc(struct
snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
shost->host_no);

+ scsi_pm_host_initialize(shost);
+
shost->ehandler = kthread_run(scsi_error_handler, shost,
"scsi_eh_%d", shost->host_no);
if (IS_ERR(shost->ehandler)) {
diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index fecba05..4fa9db4 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -1133,15 +1133,20 @@ static int __init init_scsi(void)
error = scsi_init_sysctl();
if (error)
goto cleanup_hosts;
- error = scsi_sysfs_register();
+ error = scsi_init_pm();
if (error)
goto cleanup_sysctl;
+ error = scsi_sysfs_register();
+ if (error)
+ goto cleanup_pm;

scsi_netlink_init();

printk(KERN_NOTICE "SCSI subsystem initialized\n");
return 0;

+cleanup_pm:
+ scsi_exit_pm();
cleanup_sysctl:
scsi_exit_sysctl();
cleanup_hosts:
@@ -1161,6 +1166,7 @@ static void __exit exit_scsi(void)
{
scsi_netlink_exit();
scsi_sysfs_unregister();
+ scsi_exit_pm();
scsi_exit_sysctl();
scsi_exit_hosts();
scsi_exit_devinfo();
diff --git a/drivers/scsi/scsi_error.c b/drivers/scsi/scsi_error.c
index 045a086..c838e65 100644
--- a/drivers/scsi/scsi_error.c
+++ b/drivers/scsi/scsi_error.c
@@ -468,30 +468,32 @@ static void scsi_eh_done(struct scsi_cmn

/**
* scsi_try_host_reset - ask host adapter to reset itself
- * @scmd: SCSI cmd to send hsot reset.
+ * @scmd: SCSI cmd to send host reset.
*/
static int scsi_try_host_reset(struct scsi_cmnd *scmd)
{
unsigned long flags;
int rtn;
+ struct Scsi_Host *shost = scmd->device->host;

SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Host RST\n",
__FUNCTION__));

if (!scmd->device->host->hostt->eh_host_reset_handler)
return FAILED;
-
- rtn = scmd->device->host->hostt->eh_host_reset_handler(scmd);
+ if (scsi_autoresume_host(shost) != 0)
+ return FAILED;

if (rtn == SUCCESS) {
- if (!scmd->device->host->hostt->skip_settle_delay)
+ if (!shost->hostt->skip_settle_delay)
ssleep(HOST_RESET_SETTLE_TIME);
- spin_lock_irqsave(scmd->device->host->host_lock, flags);
- scsi_report_bus_reset(scmd->device->host,
+ spin_lock_irqsave(shost->host_lock, flags);
+ scsi_report_bus_reset(shost,
scmd_channel(scmd));
- spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
+ spin_unlock_irqrestore(shost->host_lock, flags);
}

+ scsi_autosuspend_host(shost);
return rtn;
}

@@ -503,24 +505,28 @@ static int scsi_try_bus_reset(struct scs
{
unsigned long flags;
int rtn;
+ struct Scsi_Host *shost = scmd->device->host;

SCSI_LOG_ERROR_RECOVERY(3, printk("%s: Snd Bus RST\n",
__FUNCTION__));

- if (!scmd->device->host->hostt->eh_bus_reset_handler)
+ if (!shost->hostt->eh_bus_reset_handler)
+ return FAILED;
+ if (scsi_autoresume_host(shost) != 0)
return FAILED;

- rtn = scmd->device->host->hostt->eh_bus_reset_handler(scmd);
+ rtn = shost->hostt->eh_bus_reset_handler(scmd);

if (rtn == SUCCESS) {
- if (!scmd->device->host->hostt->skip_settle_delay)
+ if (!shost->hostt->skip_settle_delay)
ssleep(BUS_RESET_SETTLE_TIME);
- spin_lock_irqsave(scmd->device->host->host_lock, flags);
- scsi_report_bus_reset(scmd->device->host,
+ spin_lock_irqsave(shost->host_lock, flags);
+ scsi_report_bus_reset(shost,
scmd_channel(scmd));
- spin_unlock_irqrestore(scmd->device->host->host_lock, flags);
+ spin_unlock_irqrestore(shost->host_lock, flags);
}

+ scsi_autosuspend_host(shost);
return rtn;
}

@@ -1541,6 +1547,7 @@ static void scsi_unjam_host(struct Scsi_
int scsi_error_handler(void *data)
{
struct Scsi_Host *shost = data;
+ int autoresume_rc;

/*
* We use TASK_INTERRUPTIBLE so that the thread is not
@@ -1570,6 +1577,7 @@ int scsi_error_handler(void *data)
* what we need to do to get it up and online again (if we can).
* If we fail, we end up taking the thing offline.
*/
+ autoresume_rc = scsi_autoresume_host(shost);
if (shost->transportt->eh_strategy_handler)
shost->transportt->eh_strategy_handler(shost);
else
@@ -1583,6 +1591,8 @@ int scsi_error_handler(void *data)
* which are still online.
*/
scsi_restart_operations(shost);
+ if (autoresume_rc == 0)
+ scsi_autosuspend_host(shost);
set_current_state(TASK_INTERRUPTIBLE);
}
__set_current_state(TASK_RUNNING);
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 135c1d0..233feee 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -67,8 +67,6 @@ #undef SP

static struct kmem_cache *scsi_bidi_sdb_cache;

-static void scsi_run_queue(struct request_queue *q);
-
/*
* Function: scsi_unprep_request()
*
@@ -461,6 +459,7 @@ void scsi_device_unbusy(struct scsi_devi
spin_unlock(shost->host_lock);
spin_lock(sdev->request_queue->queue_lock);
sdev->device_busy--;
+ scsi_mark_last_busy(sdev);
spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
}

@@ -522,7 +521,7 @@ static void scsi_single_lun_run(struct s
* Notes: The previous command was completely finished, start
* a new one if possible.
*/
-static void scsi_run_queue(struct request_queue *q)
+void scsi_run_queue(struct request_queue *q)
{
struct scsi_device *sdev = q->queuedata;
struct Scsi_Host *shost = sdev->host;
@@ -1201,6 +1200,8 @@ int scsi_prep_state_check(struct scsi_de
ret = BLKPREP_KILL;
break;
case SDEV_QUIESCE:
+ ret = scsi_pm_state_check(sdev, req);
+ break;
case SDEV_BLOCK:
/*
* If the devices is blocked we defer normal commands.
diff --git a/drivers/scsi/scsi_priv.h b/drivers/scsi/scsi_priv.h
index 3f34e93..c331de4 100644
--- a/drivers/scsi/scsi_priv.h
+++ b/drivers/scsi/scsi_priv.h
@@ -4,11 +4,13 @@ #define _SCSI_PRIV_H
#include <linux/device.h>

struct request_queue;
+struct request;
struct scsi_cmnd;
struct scsi_device;
struct scsi_host_template;
struct Scsi_Host;
struct scsi_nl_hdr;
+struct workqueue_struct;


/*
@@ -67,6 +69,7 @@ int scsi_eh_get_sense(struct list_head *
extern int scsi_maybe_unblock_host(struct scsi_device *sdev);
extern void scsi_device_unbusy(struct scsi_device *sdev);
extern int scsi_queue_insert(struct scsi_cmnd *cmd, int reason);
+extern void scsi_run_queue(struct request_queue *q);
extern void scsi_next_command(struct scsi_cmnd *cmd);
extern void scsi_io_completion(struct scsi_cmnd *, unsigned int);
extern void scsi_run_host_queues(struct Scsi_Host *shost);
@@ -132,6 +135,41 @@ static inline void scsi_netlink_init(voi
static inline void scsi_netlink_exit(void) {}
#endif

+/* scsi_pm.c */
+extern int scsi_bus_suspend(struct device *, pm_message_t);
+extern int scsi_bus_resume(struct device *);
+extern int scsi_pm_state_check(struct scsi_device *, struct request *);
+extern int scsi_pm_device_stop(struct scsi_device *);
+extern int scsi_pm_host_stop(struct Scsi_Host *);
+#ifdef CONFIG_SCSI_DYNAMIC_PM
+extern void scsi_autosuspend_host(struct Scsi_Host *);
+extern int scsi_autoresume_host(struct Scsi_Host *);
+extern void scsi_pm_host_initialize(struct Scsi_Host *);
+extern void scsi_mark_last_busy(struct scsi_device *);
+extern void scsi_use_ULD_pm(struct scsi_device *, int);
+extern void scsi_autosuspend_device(struct scsi_device *);
+extern int scsi_autoresume_device(struct scsi_device *);
+extern int scsi_pm_create_device_files(struct scsi_device *);
+extern void scsi_pm_device_initialize(struct scsi_device *);
+extern int scsi_init_pm(void);
+extern void scsi_exit_pm(void);
+#else
+static inline void scsi_autosuspend_host(struct Scsi_Host *shost) {}
+static inline int scsi_autoresume_host(struct Scsi_Host *shost)
+ { return 0; }
+static inline void scsi_pm_host_initialize(struct Scsi_Host *shost) {}
+static inline void scsi_mark_last_busy(struct scsi_device *sdev) {}
+static inline void scsi_use_ULD_pm(struct scsi_device *sdev, int v) {}
+static inline void scsi_autosuspend_device(struct scsi_device *sdev) {}
+static inline int scsi_autoresume_device(struct scsi_device *sdev)
+ { return 0; }
+static inline int scsi_pm_create_device_files(struct scsi_device *sdev)
+ { return 0; }
+static inline void scsi_pm_device_initialize(struct scsi_device *sdev) {}
+static inline int scsi_init_pm(void) { return 0; }
+static inline void scsi_exit_pm(void) {}
+#endif /* CONFIG_SCSI_DYNAMIC_PM */
+
/*
* internal scsi timeout functions: for use by mid-layer and transport
* classes.
diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 1dc165a..c48a143 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -297,6 +297,9 @@ static struct scsi_device *scsi_alloc_sd
scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);

scsi_sysfs_device_initialize(sdev);
+ scsi_pm_device_initialize(sdev);
+ if (scsi_autoresume_host(shost) != 0)
+ goto out_device_destroy;

if (shost->hostt->slave_alloc) {
ret = shost->hostt->slave_alloc(sdev);
@@ -307,6 +310,7 @@ static struct scsi_device *scsi_alloc_sd
*/
if (ret == -ENXIO)
display_failure_msg = 0;
+ scsi_autosuspend_host(shost);
goto out_device_destroy;
}
}
@@ -922,6 +926,7 @@ static int scsi_add_lun(struct scsi_devi
static inline void scsi_destroy_sdev(struct scsi_device *sdev)
{
scsi_device_set_state(sdev, SDEV_DEL);
+ scsi_autosuspend_host(sdev->host);
if (sdev->host->hostt->slave_destroy)
sdev->host->hostt->slave_destroy(sdev);
transport_destroy_device(&sdev->sdev_gendev);
@@ -1084,6 +1089,7 @@ static int scsi_probe_and_add_lun(struct

res = scsi_add_lun(sdev, result, &bflags, shost->async_scan);
if (res == SCSI_SCAN_LUN_PRESENT) {
+ scsi_autosuspend_device(sdev);
if (bflags & BLIST_KEY) {
sdev->lockable = 0;
scsi_unlock_floptical(sdev, result);
@@ -1785,6 +1791,8 @@ static void scsi_finish_async_scan(struc

static void do_scsi_scan_host(struct Scsi_Host *shost)
{
+ if (scsi_autoresume_host(shost) != 0)
+ return;
if (shost->hostt->scan_finished) {
unsigned long start = jiffies;
if (shost->hostt->scan_start)
@@ -1796,6 +1804,7 @@ static void do_scsi_scan_host(struct Scs
scsi_scan_host_selected(shost, SCAN_WILD_CARD, SCAN_WILD_CARD,
SCAN_WILD_CARD, 0);
}
+ scsi_autosuspend_host(shost);
}

static int do_scan_async(void *_data)
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index ed83cdb..5393e15 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -340,54 +340,6 @@ static int scsi_bus_uevent(struct device
return 0;
}

-static int scsi_bus_suspend(struct device * dev, pm_message_t state)
-{
- struct device_driver *drv = dev->driver;
- struct scsi_device *sdev = to_scsi_device(dev);
- int err;
-
- err = scsi_device_quiesce(sdev);
- if (err)
- return err;
-
- if (drv && drv->suspend) {
- err = drv->suspend(dev, state);
- if (err)
- return err;
- }
-
- return 0;
-}
-
-static int scsi_bus_resume(struct device * dev)
-{
- struct device_driver *drv = dev->driver;
- struct scsi_device *sdev = to_scsi_device(dev);
- int err = 0;
-
- if (drv && drv->resume)
- err = drv->resume(dev);
-
- scsi_device_resume(sdev);
-
- return err;
-}
-
-static int scsi_bus_remove(struct device *dev)
-{
- struct device_driver *drv = dev->driver;
- struct scsi_device *sdev = to_scsi_device(dev);
- int err = 0;
-
- /* reset the prep_fn back to the default since the
- * driver may have altered it and it's being removed */
- blk_queue_prep_rq(sdev->request_queue, scsi_prep_fn);
-
- if (drv && drv->remove)
- err = drv->remove(dev);
-
- return 0;
-}

struct bus_type scsi_bus_type = {
.name = "scsi",
@@ -814,6 +766,12 @@ int scsi_sysfs_add_sdev(struct scsi_devi
goto out;
}

+ error = scsi_pm_create_device_files(sdev);
+ if (error) {
+ __scsi_remove_device(sdev);
+ goto out;
+ }
+
error = bsg_register_queue(rq, &sdev->sdev_gendev, NULL);

if (error)
@@ -854,7 +812,7 @@ void __scsi_remove_device(struct scsi_de
{
struct device *dev = &sdev->sdev_gendev;

- if (scsi_device_set_state(sdev, SDEV_CANCEL) != 0)
+ if (scsi_pm_device_stop(sdev) != 0)
return;

bsg_unregister_queue(sdev->request_queue);
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 37df8bb..16add9a 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -61,6 +61,7 @@ #include <scsi/scsicam.h>
#include <scsi/sd.h>

#include "scsi_logging.h"
+#include "scsi_priv.h"

MODULE_AUTHOR("Eric Youngdale");
MODULE_DESCRIPTION("SCSI disk (sd) driver");
@@ -1649,6 +1650,10 @@ static int sd_probe(struct device *dev)
if (error)
goto out_put;

+ error = scsi_autoresume_device(sdp);
+ if (error)
+ goto out_put;
+
sdkp->device = sdp;
sdkp->driver = &sd_template;
sdkp->disk = gd;
@@ -1668,7 +1673,7 @@ static int sd_probe(struct device *dev)
strncpy(sdkp->cdev.class_id, sdp->sdev_gendev.bus_id, BUS_ID_SIZE);

if (class_device_add(&sdkp->cdev))
- goto out_put;
+ goto out_suspend;

get_device(&sdp->sdev_gendev);

@@ -1708,8 +1713,12 @@ static int sd_probe(struct device *dev)
sd_printk(KERN_NOTICE, sdkp, "Attached SCSI %sdisk\n",
sdp->removable ? "removable " : "");

+ scsi_use_ULD_pm(sdp, 1);
+ scsi_autosuspend_device(sdp);
return 0;

+ out_suspend:
+ scsi_autosuspend_device(sdp);
out_put:
put_disk(gd);
out_free:
@@ -1735,6 +1744,7 @@ static int sd_remove(struct device *dev)

class_device_del(&sdkp->cdev);
del_gendisk(sdkp->disk);
+ scsi_use_ULD_pm(sdkp->device, 0);
sd_shutdown(dev);

mutex_lock(&sd_ref_mutex);
diff --git a/drivers/scsi/sg.c b/drivers/scsi/sg.c
index e5156aa..27e3669 100644
--- a/drivers/scsi/sg.c
+++ b/drivers/scsi/sg.c
@@ -57,6 +57,7 @@ #include <scsi/scsi_driver.h>
#include <scsi/scsi_ioctl.h>
#include <scsi/sg.h>

+#include "scsi_priv.h"
#include "scsi_logging.h"

#ifdef CONFIG_SCSI_PROC_FS
@@ -226,6 +227,7 @@ sg_open(struct inode *inode, struct file
Sg_fd *sfp;
int res;
int retval;
+ int autoresume_rc = 1;

nonseekable_open(inode, filp);
SCSI_LOG_TIMEOUT(3, printk("sg_open: dev=%d, flags=0x%x\n", dev, flags));
@@ -241,6 +243,10 @@ sg_open(struct inode *inode, struct file
if (retval)
return retval;

+ retval = autoresume_rc = scsi_autoresume_device(sdp->device);
+ if (retval)
+ goto error_out;
+
if (!((flags & O_NONBLOCK) ||
scsi_block_when_processing_errors(sdp->device))) {
retval = -ENXIO;
@@ -298,6 +304,8 @@ sg_open(struct inode *inode, struct file
return 0;

error_out:
+ if (autoresume_rc == 0)
+ scsi_autosuspend_device(sdp->device);
scsi_device_put(sdp->device);
return retval;
}
@@ -313,6 +321,8 @@ sg_release(struct inode *inode, struct f
return -ENXIO;
SCSI_LOG_TIMEOUT(3, printk("sg_release: %s\n", sdp->disk->disk_name));
sg_fasync(-1, filp, 0); /* remove filp from async notification list */
+ scsi_autosuspend_device(sdp->device);
+
if (0 == sg_remove_sfp(sdp, sfp)) { /* Returns 1 when sdp gone */
if (!sdp->detached) {
scsi_device_put(sdp->device);
diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index 8c1e295..ca954fa 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -299,10 +299,15 @@ static int device_reset(struct scsi_cmnd

US_DEBUGP("%s called\n", __FUNCTION__);

- /* lock the device pointers and do the reset */
- mutex_lock(&(us->dev_mutex));
- result = us->transport_reset(us);
- mutex_unlock(&us->dev_mutex);
+ result = usb_autopm_get_interface(us->pusb_intf);
+ if (result == 0) {
+
+ /* lock the device pointers and do the reset */
+ mutex_lock(&(us->dev_mutex));
+ result = us->transport_reset(us);
+ mutex_unlock(&us->dev_mutex);
+ usb_autopm_put_interface(us->pusb_intf);
+ }

return result < 0 ? FAILED : SUCCESS;
}
@@ -345,6 +350,24 @@ void usb_stor_report_bus_reset(struct us
scsi_unlock(host);
}

+/* The host and its devices are all idle so we can autosuspend */
+static int autosuspend(struct Scsi_Host *host)
+{
+ struct us_data *us = host_to_us(host);
+
+ usb_autopm_put_interface(us->pusb_intf);
+ return 0;
+}
+
+/* The host needs to be autoresumed */
+static int autoresume(struct Scsi_Host *host)
+{
+ struct us_data *us = host_to_us(host);
+
+ return usb_autopm_get_interface(us->pusb_intf);
+}
+
+
/***********************************************************************
* /proc/scsi/ functions
***********************************************************************/
@@ -471,6 +494,10 @@ struct scsi_host_template usb_stor_host_
.eh_device_reset_handler = device_reset,
.eh_bus_reset_handler = bus_reset,

+ /* dynamic power management */
+ .autosuspend = autosuspend,
+ .autoresume = autoresume,
+
/* queue commands only, only one command per LUN */
.can_queue = 1,
.cmd_per_lun = 1,
diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
index ac6114e..a574646 100644
--- a/drivers/usb/storage/usb.c
+++ b/drivers/usb/storage/usb.c
@@ -184,16 +184,14 @@ static int storage_suspend(struct usb_in
{
struct us_data *us = usb_get_intfdata(iface);

+ US_DEBUGP("%s\n", __FUNCTION__);
+
/* Wait until no command is running */
mutex_lock(&us->dev_mutex);

- US_DEBUGP("%s\n", __FUNCTION__);
if (us->suspend_resume_hook)
(us->suspend_resume_hook)(us, US_SUSPEND);

- /* When runtime PM is working, we'll set a flag to indicate
- * whether we should autoresume when a SCSI request arrives. */
-
mutex_unlock(&us->dev_mutex);
return 0;
}
@@ -202,13 +200,10 @@ static int storage_resume(struct usb_int
{
struct us_data *us = usb_get_intfdata(iface);

- mutex_lock(&us->dev_mutex);
-
US_DEBUGP("%s\n", __FUNCTION__);
if (us->suspend_resume_hook)
(us->suspend_resume_hook)(us, US_RESUME);

- mutex_unlock(&us->dev_mutex);
return 0;
}

@@ -928,6 +923,7 @@ static int usb_stor_scan_thread(void * _
/* Should we unbind if no devices were detected? */
}

+ usb_autopm_put_interface(us->pusb_intf);
complete_and_exit(&us->scanning_done, 0);
}

@@ -957,6 +953,9 @@ static int storage_probe(struct usb_inte
return -ENOMEM;
}

+ /* Don't autosuspend until the SCSI core tells us */
+ usb_autopm_get_interface(intf);
+
/*
* Allow 16-byte CDBs and thus > 2TB
*/
@@ -1017,6 +1016,7 @@ static int storage_probe(struct usb_inte
goto BadDevice;
}

+ usb_autopm_get_interface(intf); /* dropped in the scanning thread */
wake_up_process(th);

return 0;
@@ -1054,6 +1054,7 @@ #endif
.pre_reset = storage_pre_reset,
.post_reset = storage_post_reset,
.id_table = storage_usb_ids,
+ .supports_autosuspend = 1,
};

static int __init usb_stor_init(void)
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index ab7acbe..1c181c4 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -36,8 +36,9 @@ enum scsi_device_state {
* Only error handler commands allowed */
SDEV_DEL, /* device deleted
* no commands allowed */
- SDEV_QUIESCE, /* Device quiescent. No block commands
- * will be accepted, only specials (which
+ SDEV_QUIESCE, /* Device quiescent or suspended.
+ * No block commands will be accepted,
+ * only specials (which
* originate in the mid-layer) */
SDEV_OFFLINE, /* Device offlined (by error handling or
* user request */
@@ -161,6 +162,24 @@ #define SCSI_DEFAULT_DEVICE_BLOCKED 3

struct execute_work ew; /* used to get process context on put */

+#ifdef CONFIG_SCSI_DYNAMIC_PM
+ struct mutex pm_mutex; /* protect PM data & operations */
+ struct work_struct autoresume_work;
+
+ unsigned long last_busy; /* time of last use */
+ int autosuspend_delay; /* delay in jiffies */
+ int pm_usage_cnt; /* usage counter for autosuspend */
+
+ unsigned is_suspended:1;
+ unsigned pm_in_progress:1; /* performing suspend or resume */
+ unsigned auto_pm:1; /* doing autosuspend or autoresume */
+ unsigned autosuspend_disabled:1; /* autosuspend & autoresume */
+ unsigned autoresume_disabled:1; /* disabled by the user */
+ unsigned skip_sys_resume:1; /* skip the next system resume */
+ unsigned use_ULD_pm:1; /* call the Upper-Level Driver's
+ * suspend/resume methods */
+#endif /* CONFIG_SCSI_DYNAMIC_PM */
+
enum scsi_device_state sdev_state;
unsigned long sdev_data[0];
} __attribute__((aligned(sizeof(unsigned long))));
diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index 530ff4c..906c4b5 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -176,6 +176,22 @@ #endif
int (* eh_host_reset_handler)(struct scsi_cmnd *);

/*
+ * Power management routines. These are optional; you should
+ * implement them if you want your LLD to perform dynamic Power
+ * Management. The autosuspend method will be called whenever
+ * all the devices below a host have been suspended (are in an
+ * idle state), at which time the host adapter can safely be
+ * autosuspended. The autoresume method will be called whenever
+ * a suspended host must be resumed for one of its devices to
+ * carry out a command. Both routines are always called in a
+ * process context with interrupts enabled.
+ *
+ * Status: OPTIONAL
+ */
+ int (* autosuspend)(struct Scsi_Host *);
+ int (* autoresume)(struct Scsi_Host *);
+
+ /*
* Before the mid layer attempts to scan for a new device where none
* currently exists, it will call this entry in your driver. Should
* your driver need to allocate any structs or perform any other init
@@ -657,6 +673,14 @@ struct Scsi_Host {
struct device shost_gendev;
struct class_device shost_classdev;

+#ifdef CONFIG_SCSI_DYNAMIC_PM
+ struct mutex pm_mutex; /* protect PM data & operations */
+ struct delayed_work autosuspend_work;
+
+ int pm_usage_cnt; /* usage counter for autosuspend */
+ unsigned is_suspended:1;
+#endif /* CONFIG_SCSI_DYNAMIC_PM */
+
/*
* List of hosts per template.
*