Patchwork [v3,2/7] scsi: pm: use autosuspend if device supports it

login
register
mail settings
Submitter Aaron Lu
Date July 26, 2012, 10:05 a.m.
Message ID <1343297129-28174-3-git-send-email-aaron.lu@amd.com>
Download mbox | patch
Permalink /patch/173391/
State Not Applicable
Delegated to: David Miller
Headers show

Comments

Aaron Lu - July 26, 2012, 10:05 a.m.
If the device is using autosuspend, when scsi_autopm_put_device is
called for it, use autosuspend runtime pm calls instead of the sync
call.

Signed-off-by: Aaron Lu <aaron.lu@amd.com>
---
 drivers/scsi/scsi_pm.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
Oliver Neukum - July 26, 2012, 10:44 a.m.
On Thursday 26 July 2012 18:05:24 Aaron Lu wrote:
> If the device is using autosuspend, when scsi_autopm_put_device is
> called for it, use autosuspend runtime pm calls instead of the sync
> call.

What is the purpose of this approach?
You need a very good reason to have an API do two different things
based on this.

	Regards
		Oliver

--
To unsubscribe from this list: send the line "unsubscribe linux-ide" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Aaron Lu - July 26, 2012, 12:43 p.m.
On Thu, Jul 26, 2012 at 12:44:24PM +0200, Oliver Neukum wrote:
> On Thursday 26 July 2012 18:05:24 Aaron Lu wrote:
> > If the device is using autosuspend, when scsi_autopm_put_device is
> > called for it, use autosuspend runtime pm calls instead of the sync
> > call.
> 
> What is the purpose of this approach?

The purpose is to let scsi layer driver(sd, sr, etc.) use the same pm
api(scsi_autopm_put_device) to put the device to runtime suspended
state.
When the device is ready to be suspended, if it does not make use of
autosuspend, call pm_runtime_put_sync for it; if it makes use of
autosuspend, call the autosuspend runtime pm apis for it.

> You need a very good reason to have an API do two different things
> based on this.

If you see the above reason not good, I'll prepare an updated version
to create a new api to cover the autosuspend case, something like:
void scsi_autopm_put_device_autosuspend(struct scsi_device *sdev)
{
	pm_runtime_mark_last_busy(&sdev->sdev_gendev);
	pm_runtime_put_autosuspend(&sdev->sdev_gendev);
}
Does this look right?

Thanks,
Aaron
--
To unsubscribe from this list: send the line "unsubscribe linux-ide" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Oliver Neukum - July 26, 2012, 1:01 p.m.
On Thursday 26 July 2012 20:43:32 Aaron Lu wrote:
> > What is the purpose of this approach?
> 
> The purpose is to let scsi layer driver(sd, sr, etc.) use the same pm
> api(scsi_autopm_put_device) to put the device to runtime suspended
> state.
> When the device is ready to be suspended, if it does not make use of
> autosuspend, call pm_runtime_put_sync for it; if it makes use of
> autosuspend, call the autosuspend runtime pm apis for it.
> 
> > You need a very good reason to have an API do two different things
> > based on this.
> 
> If you see the above reason not good, I'll prepare an updated version
> to create a new api to cover the autosuspend case, something like:
> void scsi_autopm_put_device_autosuspend(struct scsi_device *sdev)
> {
>         pm_runtime_mark_last_busy(&sdev->sdev_gendev);
>         pm_runtime_put_autosuspend(&sdev->sdev_gendev);
> }
> Does this look right?

Much better :-)

	Regards
		Oliver

--
To unsubscribe from this list: send the line "unsubscribe linux-ide" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch

diff --git a/drivers/scsi/scsi_pm.c b/drivers/scsi/scsi_pm.c
index dc0ad85..7c93723 100644
--- a/drivers/scsi/scsi_pm.c
+++ b/drivers/scsi/scsi_pm.c
@@ -197,7 +197,13 @@  EXPORT_SYMBOL_GPL(scsi_autopm_get_device);
 
 void scsi_autopm_put_device(struct scsi_device *sdev)
 {
-	pm_runtime_put_sync(&sdev->sdev_gendev);
+	if (sdev->sdev_gendev.power.use_autosuspend) {
+		pm_runtime_mark_last_busy(&sdev->sdev_gendev);
+		pm_runtime_put_autosuspend(&sdev->sdev_gendev);
+	} else {
+		pm_runtime_put_sync(&sdev->sdev_gendev);
+	}
+
 }
 EXPORT_SYMBOL_GPL(scsi_autopm_put_device);