For ODDs, the upper layer will poll for media change every a few
seconds, which will make it enter and leave suspend state very
oftern. And as each suspend will also cause a hard/soft reset,
the gain of runtime suspend is very little while the ODD may
mis-function after constantly being reset. So the idle callback
here will not proceed to suspend if a non-ZPODD capable ODD is
attached to the port.
Signed-off-by: Aaron Lu <aaron.lu@xxxxxxxxx>
---
drivers/ata/libata-core.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index 97987e7..9cdfb04 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -5406,8 +5406,27 @@ static int ata_port_resume(struct device *dev)
return rc;
}
+/*
+ * For ODDs, the upper layer will poll for media change every a few seconds,
+ * which will make it enter and leave suspend state every a few seconds. And
+ * as each suspend will cause a hard/soft reset, the gain of runtime suspend
+ * is very little and the ODD may mis-function after constantly being reset.
+ * So the idle callback here will not proceed to suspend if a non-ZPODD capable
+ * ODD is attached to the port.
+ */
static int ata_port_runtime_idle(struct device *dev)
{
+ struct ata_port *ap = to_ata_port(dev);
+ struct ata_link *link;
+ struct ata_device *adev;
+
+ ata_for_each_link(link, ap, HOST_FIRST) {
+ ata_for_each_dev(adev, link, ENABLED)
+ if (adev->class == ATA_DEV_ATAPI &&
+ !zpodd_dev_enabled(adev))
+ return -EBUSY;
+ }
+
return pm_runtime_suspend(dev);
}
--
1.7.12.4
--
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