Re: Power management for SCSI
- From: Pavel Machek <pavel@xxxxxxx>
- Date: Thu, 14 Aug 2008 17:56:49 +0200
Hi!
...Add support for autosuspend/autoresume. Lowlevel driver can use it to
spin the disk down and power down its SATA link, to turn off the USB
interface, etc.
Spinning down the disk is useful - saves ~0.5W here. Powering down
SATA controller is even better -- should save ~1W.
Now, I guess the patch will need to be split to small pieces for
merge... I tried to rearrange it so that the documentation and hooks
go before stuff that needs the hooks, and before Kconfig enabler. If
it looks reasonably good, I'll split it into smaller pieces.
James had a number of objections to my original patch; you can read
them here:
https://lists.linux-foundation.org/pipermail/linux-pm/2008-March/016849.html
I haven't had time yet to work on an improved version.
Ok, I see, "its done at the wrong level" sounds pretty serious.
First the general comments/questions:
#2. As you say in the comment, the thing we're trying to power down is
#the link. In most SCSI implementations, the link has a rather complex
#relationship to the target, what we want to do in
#periodic_autosuspend_scan() is run over the devices on each link, and
#if
#they're not busy suspend the link? What's probably needed is a set of
#adjunct helpers for the transport classes to do this.
So the host suspend/resume stuff should go into struct
scsi_transport_template?
Is this step in the right direction? Moved autosuspend from
scsi_host_template to scsi_transport_template...
Pavel
diff --git a/drivers/ata/ahci.c b/drivers/ata/ahci.c
index e4864d9..2b8cf09 100644
--- a/drivers/ata/ahci.c
+++ b/drivers/ata/ahci.c
@@ -320,14 +320,14 @@ static struct device_attribute *ahci_sde
};
struct pci_dev *my_pdev;
-int autosuspend_enabled = 0; /* HERE */
+int autosuspend_enabled = 1; /* HERE */
struct sleep_disabled_reason ahci_active = {
"ahci"
};
/* The host and its devices are all idle so we can autosuspend */
-static int autosuspend(struct Scsi_Host *host)
+int ahci_autosuspend(struct Scsi_Host *host)
{
if (my_pdev && autosuspend_enabled) {
printk("ahci: should autosuspend\n");
@@ -340,7 +340,7 @@ static int autosuspend(struct Scsi_Host
}
/* The host needs to be autoresumed */
-static int autoresume(struct Scsi_Host *host)
+int ahci_autoresume(struct Scsi_Host *host)
{
if (my_pdev && autosuspend_enabled) {
printk("ahci: should autoresume\n");
@@ -360,8 +360,8 @@ static struct scsi_host_template ahci_sh
.sg_tablesize = AHCI_MAX_SG,
.dma_boundary = AHCI_DMA_BOUNDARY,
.shost_attrs = ahci_shost_attrs,
- .autosuspend = autosuspend,
- .autoresume = autoresume,
+// .autosuspend = autosuspend,
+// .autoresume = autoresume,
.sdev_attrs = ahci_sdev_attrs,
};
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index b9d3ba4..d3526a0 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -103,6 +103,9 @@ static const u8 def_control_mpage[CONTRO
0, 30 /* extended self test time, see 05-359r1 */
};
+int ahci_autosuspend(struct Scsi_Host *host);
+int ahci_autoresume(struct Scsi_Host *host);
+
/*
* libata transport template. libata doesn't do real transport stuff.
* It just needs the eh_timed_out hook.
@@ -111,6 +114,8 @@ static struct scsi_transport_template at
.eh_strategy_handler = ata_scsi_error,
.eh_timed_out = ata_scsi_timed_out,
.user_scan = ata_scsi_user_scan,
+ .autosuspend = ahci_autosuspend,
+ .autoresume = ahci_autoresume,
};
diff --git a/drivers/scsi/scsi_pm.c b/drivers/scsi/scsi_pm.c
index 5ef69c4..d2de371 100644
--- a/drivers/scsi/scsi_pm.c
+++ b/drivers/scsi/scsi_pm.c
@@ -10,6 +10,7 @@ #define DEBUG
#include <scsi/scsi.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
+#include <scsi/scsi_transport.h>
#include <linux/delay.h>
@@ -50,8 +51,8 @@ void scsi_autosuspend_host(struct Scsi_H
if (shost->pm_usage_cnt <= 0 && !shost->is_suspended &&
shost->shost_state == SHOST_RUNNING) {
WARN_ON(shost->host_busy);
- if (!shost->hostt->autosuspend ||
- shost->hostt->autosuspend(shost) == 0) {
+ if (!shost->transportt->autosuspend ||
+ shost->transportt->autosuspend(shost) == 0) {
shost->is_suspended = 1;
shost_dbg(shost, "suspended\n");
}
@@ -82,10 +83,10 @@ int scsi_autoresume_host(struct Scsi_Hos
mutex_lock(&shost->pm_mutex);
++shost->pm_usage_cnt;
if (shost->is_suspended) {
- if (shost->hostt->autoresume &&
+ if (shost->transportt->autoresume &&
(shost->shost_state == SHOST_RUNNING ||
shost->shost_state == SHOST_RECOVERY))
- status = shost->hostt->autoresume(shost);
+ status = shost->transportt->autoresume(shost);
if (status == 0) {
shost->is_suspended = 0;
shost_dbg(shost, "resumed\n");
diff --git a/drivers/usb/storage/scsiglue.c b/drivers/usb/storage/scsiglue.c
index ef64fd8..c96f11f 100644
--- a/drivers/usb/storage/scsiglue.c
+++ b/drivers/usb/storage/scsiglue.c
@@ -499,10 +499,6 @@ 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/include/scsi/scsi_host.h b/include/scsi/scsi_host.h
index b60445f..0f30451 100644
--- a/include/scsi/scsi_host.h
+++ b/include/scsi/scsi_host.h
@@ -176,21 +176,6 @@ #endif
int (* eh_bus_reset_handler)(struct scsi_cmnd *);
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
diff --git a/include/scsi/scsi_transport.h b/include/scsi/scsi_transport.h
index 490bd13..15c7886 100644
--- a/include/scsi/scsi_transport.h
+++ b/include/scsi/scsi_transport.h
@@ -77,6 +77,22 @@ struct scsi_transport_template {
* request for target drivers.
*/
int (* tsk_mgmt_response)(struct Scsi_Host *, u64, u64, int);
+
+ /*
+ * 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 *);
};
#define transport_class_to_shost(tc) \
--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
- References:
- Power management for SCSI
- From: Pavel Machek
- Re: Power management for SCSI
- From: Alan Stern
- Re: Power management for SCSI
- From: Pavel Machek
- Power management for SCSI
- Prev by Date: Re: [PATCH RFC] pm_qos_requirement might sleep
- Next by Date: Re: TALPA - a threat model? well sorta.
- Previous by thread: Re: Power management for SCSI
- Next by thread: Re: Power management for SCSI
- Index(es):
Relevant Pages
|
Loading
