Commit 5c6fab9d authored Feb 18, 2016 by Mika Westerberg Committed by Tejun Heo Feb 19, 2016

scsi: Drop runtime PM usage count after host is added



Runtime PM of the SCSI host is already handled by calls to
scsi_autopm_get_host() and scsi_autopm_put_host() from appropriate places
whenever the host needs to be powered on. This works fine when there is
device connected to the host as once it runtime suspends the host will too.

However, if there is no device connected the host is never runtime
suspended (the usage counter is always 0).

Allow runtime suspend of host even if it has no devices connected by
calling scsi_autopm_put_host() at the end of scsi_add_host_with_dma(). We
temporarily increase runtime PM usage counter first so call to
scsi_autopm_put_host() will result idle request to be scheduled for the
device.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>

parent 356fd266

drivers/scsi/hosts.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -250,6 +250,12 @@ int scsi_add_host_with_dma(struct Scsi_Host shost, struct device dev,
		if (error)
		goto out_destroy_freelist;

		/*
		* Increase usage count temporarily here so that calling
		* scsi_autopm_put_host() will trigger runtime idle if there is
		* nothing else preventing suspending the device.
		*/
		pm_runtime_get_noresume(&shost->shost_gendev);
		pm_runtime_set_active(&shost->shost_gendev);
		pm_runtime_enable(&shost->shost_gendev);
		device_enable_async_suspend(&shost->shost_gendev);
		@@ -290,6 +296,7 @@ int scsi_add_host_with_dma(struct Scsi_Host shost, struct device dev,
		goto out_destroy_host;

		scsi_proc_host_add(shost);
		scsi_autopm_put_host(shost);
		return error;

		out_destroy_host:

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