Re: [PATCH v5 5/6] ata: add ata port system PM callbacks

Lin Ming
2011-12-13T14:20:40Z

On Tue, 2011-12-13 at 21:56 +0800, Lin Ming wrote:
> +
> +static int ata_port_resume(struct device *dev)
> +{
> + struct ata_port *ap = to_ata_port(dev);
> + int rc;
> +
> + rc = ata_port_request_pm(ap, PMSG_ON, ATA_EH_RESET,
> + ATA_EHI_NO_AUTOPSY | ATA_EHI_QUIET, 1);
> + return rc;
> +}

I just realized that the ata port runtime PM status need to be updated
after system resume.

I tried below patch.
Unfortunately, it causes a problem that sd can't resume correctly.

During system resume, ata port is resumed first and then sd resumed.

When ata port resumed, device_resume(...) calls pm_runtime_put_sync(..),
which causes ata port to be runtime suspended immediately.

So sd resume fails because it requires ata port to be active to handle
start device command.

This seems a PM core's bug.

device_resume(...) should not runtime suspend the parent device, because
its children have not resumed yet.

Alan,

What do you think?

---
drivers/ata/libata-core.c | 18 ++++++++++++++++--
1 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 15a3d4d..8996758 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -5298,7 +5298,7 @@ static int ata_port_suspend(struct device *dev)
return ata_port_suspend_common(dev);
}

-static int ata_port_resume(struct device *dev)
+static int ata_port_resume_common(struct device *dev)
{
struct ata_port *ap = to_ata_port(dev);
int rc;
@@ -5308,6 +5308,20 @@ static int ata_port_resume(struct device *dev)
return rc;
}

+static int ata_port_resume(struct device *dev)
+{
+ int rc;
+
+ rc = ata_port_resume_common(dev);
+ if (!rc) {
+ pm_runtime_disable(dev);
+ pm_runtime_set_active(dev);
+ pm_runtime_enable(dev);
+ }
+
+ return rc;
+}
+
static int ata_port_runtime_idle(struct device *dev)
{
return pm_runtime_suspend(dev);
@@ -5318,7 +5332,7 @@ static const struct dev_pm_ops ata_port_pm_ops = {
.resume = ata_port_resume,

.runtime_suspend = ata_port_suspend_common,
- .runtime_resume = ata_port_resume,
+ .runtime_resume = ata_port_resume_common,
.runtime_idle = ata_port_runtime_idle,
};