Thread (11 messages) flat view 11 messages, 1 author, 2012-11-21
STALE5057d

Revision v10 of 3 in this series.

Revisions (3)
  1. v8 [diff vs current]
  2. v9 [diff vs current]
  3. v10 current

[PATCH v10 10/10] libata: do not suspend port if normal ODD is attached

From: Aaron Lu <hidden>
Date: 2012-11-21 11:50:39
Also in: linux-acpi
Subsystem: libata subsystem (serial and parallel ata drivers), the rest · Maintainers: Damien Le Moal, Niklas Cassel, Linus Torvalds

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 <redacted>
---
 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
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help