ZPODD Patches

Added a new config CONFIG_SATA_ZPODD, which is used to support SATA based zero power ODD(ZPODD), and depends on ATA_ACPI.

Signed-off-by Aaron Lu <[email protected]>

drivers/ata/libata-acpi.c +4 -0

+
+	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
+	tf.command = ATA_CMD_PACKET;
+

+/*
+ * Per the spec, only slot type and drawer type ODD can be supported
+ *
+ * Return 0 for slot type, 1 for drawer, -ENODEV for other types or on error.
+ */

drivers/ata/libata-acpi.c +78 -0

+static int check_loading_mechanism(struct ata_device *dev)
+{
+	char buf[16];
+	unsigned int ret;
+	struct rm_feature_desc *desc = (void *)(buf + 8);
+
+	char cdb[] = {  GPCMD_GET_CONFIGURATION,
+			2,      /* only 1 feature descriptor requested */
+			0, 3,   /* 3, removable medium feature */
+			0, 0, 0,/* reserved */
+			0, sizeof(buf),
+			0, 0, 0,
+	};
+
+	ret = run_atapi_cmd(dev, cdb, sizeof(cdb), buf, sizeof(buf));
+	if (ret)
+		return -ENODEV;
+
+	if (be16_to_cpu(desc->feature_code) != 3)
+		return -ENODEV;
+
+	if (desc->mech_type == 0 && desc->load == 0 && desc->eject == 1)
+		return 0; /* slot */
+	else if (desc->mech_type == 1 && desc->load == 0 && desc->eject == 1)
+		return 1; /* drawer */
+	else
+		return -ENODEV;
+}
+
+static bool odd_can_poweroff(struct ata_device *ata_dev)
+{
+	acpi_handle handle;
+	acpi_status status;
+	struct acpi_device *acpi_dev;
+
+	handle = ata_dev_acpi_handle(ata_dev);
+	if (!handle)
+		return false;
+
+	status = acpi_bus_get_device(handle, &acpi_dev);
+	if (ACPI_FAILURE(status))
+		return false;
+
+	return acpi_device_can_poweroff(acpi_dev);
+}
+
+void zpodd_init(struct ata_device *dev)
+{
+	int ret;
+	struct zpodd *zpodd;
+
+	if (dev->zpodd)
+		return;
+
+	if (!odd_can_poweroff(dev))
+		return;
+
+	if ((ret = check_loading_mechanism(dev)) == -ENODEV)
+		return;
+
+	zpodd = kzalloc(sizeof(struct zpodd), GFP_KERNEL);
+	if (!zpodd)
+		return;
+
+	if (ret)
+		zpodd->drawer = true;
+	else
+		zpodd->slot = true;
+
+	zpodd->dev = dev;
+	dev->zpodd = zpodd;
+}
+
+void zpodd_exit(struct ata_device *dev)
+{
+	kfree(dev->zpodd);
+	dev->zpodd = NULL;
+}

drivers/ata/libata.h +0 -0

index 7148a58..8cb4372 100644

Quoted 6 lines · Aaron Lu

drivers/ata/libata-acpi.c +0 -0

index ef01ac0..5aa7322 100644
@@ -1063,6 +1063,8 @@ void ata_acpi_bind(struct ata_device *dev)
 

drivers/ata/libata-acpi.c void ata_acpi_bind(struct ata_device *dev) · line 1070

Quoted 7 lines

drivers/ata/libata-acpi.c +2 -0

 void ata_acpi_unbind(struct ata_device *dev)
 {
+	if (zpodd_dev_enabled(dev))
+		zpodd_exit(dev);
 	ata_acpi_remove_pm_notifier(dev);
 	ata_acpi_unregister_power_resource(dev);
 }

Wouldn't it make more sense to invoke zpodd_exit() from ata_scsi_remove_dev() which is approximate counterpart of dev_configure?

drivers/ata/libata-acpi.c

Quoted 7 lines

drivers/ata/libata-acpi.c +6 -0

+struct zpodd {
+	bool slot:1;
+	bool drawer:1;
+
+	struct ata_device *dev;
+};

Field names are usually indented. It would be nice to have a comment

explaining synchronization. Bitfields w/ their implicit RMW ops tend to make people wonder about what the access rules are.

drivers/ata/libata-acpi.c

Quoted 5 lines

drivers/ata/libata-acpi.c +4 -0

+static int run_atapi_cmd(struct ata_device *dev, const char *cdb,
+		unsigned short cdb_len, char *buf, unsigned int buf_len)
+{
+	struct ata_taskfile tf = {0};

No need for 0. { } is enough and more generic.

Quoted 12 lines

drivers/ata/libata-acpi.c +11 -0

+
+	tf.flags |= ATA_TFLAG_ISADDR | ATA_TFLAG_DEVICE;
+	tf.command = ATA_CMD_PACKET;
+
+	if (buf) {
+		tf.protocol = ATAPI_PROT_PIO;
+		tf.lbam = buf_len;
+	} else {
+		tf.protocol = ATAPI_PROT_NODATA;
+	}
+

drivers/ata/libata-acpi.c

Quoted 3 lines

drivers/ata/libata-acpi.c +3 -0

+	return ata_exec_internal(dev, &tf, cdb,
+			buf ? DMA_FROM_DEVICE : DMA_NONE, buf, buf_len, 0);
+}

So, the function name is a bit of misnomer given that ATAPI commands are not limited to PIO or DMA_FROM_DEVICE. Also, this function ends up being used twice - once w/ read buffer and once w/o. Do we really want this function? It's not like exec_internal is difficult to use.

Quoted 6 lines

+/*
+ * Per the spec, only slot type and drawer type ODD can be supported
+ *
+ * Return 0 for slot type, 1 for drawer, -ENODEV for other types or on error.
+ */

Maybe bool odd_has_drawer() is better?

Quoted 84 lines

drivers/ata/libata-acpi.c +78 -0

+static int check_loading_mechanism(struct ata_device *dev)
+{
+	char buf[16];
+	unsigned int ret;
+	struct rm_feature_desc *desc = (void *)(buf + 8);
+
+	char cdb[] = {  GPCMD_GET_CONFIGURATION,
+			2,      /* only 1 feature descriptor requested */
+			0, 3,   /* 3, removable medium feature */
+			0, 0, 0,/* reserved */
+			0, sizeof(buf),
+			0, 0, 0,
+	};
+
+	ret = run_atapi_cmd(dev, cdb, sizeof(cdb), buf, sizeof(buf));
+	if (ret)
+		return -ENODEV;
+
+	if (be16_to_cpu(desc->feature_code) != 3)
+		return -ENODEV;
+
+	if (desc->mech_type == 0 && desc->load == 0 && desc->eject == 1)
+		return 0; /* slot */
+	else if (desc->mech_type == 1 && desc->load == 0 && desc->eject == 1)
+		return 1; /* drawer */
+	else
+		return -ENODEV;
+}
+
+static bool odd_can_poweroff(struct ata_device *ata_dev)
+{
+	acpi_handle handle;
+	acpi_status status;
+	struct acpi_device *acpi_dev;
+
+	handle = ata_dev_acpi_handle(ata_dev);
+	if (!handle)
+		return false;
+
+	status = acpi_bus_get_device(handle, &acpi_dev);
+	if (ACPI_FAILURE(status))
+		return false;
+
+	return acpi_device_can_poweroff(acpi_dev);
+}
+
+void zpodd_init(struct ata_device *dev)
+{
+	int ret;
+	struct zpodd *zpodd;
+
+	if (dev->zpodd)
+		return;
+
+	if (!odd_can_poweroff(dev))
+		return;
+
+	if ((ret = check_loading_mechanism(dev)) == -ENODEV)
+		return;
+
+	zpodd = kzalloc(sizeof(struct zpodd), GFP_KERNEL);
+	if (!zpodd)
+		return;
+
+	if (ret)
+		zpodd->drawer = true;
+	else
+		zpodd->slot = true;
+
+	zpodd->dev = dev;
+	dev->zpodd = zpodd;
+}
+
+void zpodd_exit(struct ata_device *dev)
+{
+	kfree(dev->zpodd);
+	dev->zpodd = NULL;
+}

drivers/ata/libata.h +0 -0

index 7148a58..8cb4372 100644

drivers/ata/libata.h static inline void ata_sff_exit(void) · line 239

Quoted 10 lines

drivers/ata/libata.h +7 -0

@@ -230,4 +230,18 @@ static inline void ata_sff_exit(void)
 { }
 #endif /* CONFIG_ATA_SFF */
 
+/* libata-zpodd.c */
+#ifdef CONFIG_SATA_ZPODD
+void zpodd_init(struct ata_device *dev);
+void zpodd_exit(struct ata_device *dev);
+static inline bool zpodd_dev_enabled(struct ata_device *dev)
+{
+	return dev->zpodd ? true : false;

	return dev->zpodd or return dev->zpodd != NULL?

Other than the above nits, looks okay to me.

Quoted 8 lines

drivers/ata/libata-zpodd.c line 11

Quoted 6 lines

drivers/ata/libata-zpodd.c new file +6 -0

+struct zpodd {
+	bool slot:1;
+	bool drawer:1;
+
+	struct ata_device *dev;
+};

Field names are usually indented. It would be nice to have a comment

checkscript.sh doesn't seem like this if I put a tab around the ':'

ERROR: spaces prohibited around that ':' (ctx:VxW) #222: FILE: include/uapi/linux/cdrom.h:915:

(quoted diff) +1 -0

+	__u8 reserved1:		2;
 	              ^

Which style should I follow?

Quoted 2 lines

explaining synchronization. Bitfields w/ their implicit RMW ops tend to make people wonder about what the access rules are.

The slot and drawer bit field is assigned only once during ata probe time in EH context, and accessed later in PM's callback context. Not sure what access rule should I describe...

Quoted 7 lines

Quoted 5 lines

+/*
+ * Per the spec, only slot type and drawer type ODD can be supported
+ *
+ * Return 0 for slot type, 1 for drawer, -ENODEV for other types or on error.
+ */

Maybe bool odd_has_drawer() is better?

There are other types of ODD other than slot and drawer, and both slot and drawer type ODDs can be supported for ZPODD. So a bool can't convey such information :-)

Hello, Aaron.

Quoted 16 lines · Aaron Lu

Quoted 8 lines

drivers/ata/libata-zpodd.c line 11

Quoted 6 lines

drivers/ata/libata-zpodd.c new file +6 -0

+struct zpodd {
+	bool slot:1;
+	bool drawer:1;
+
+	struct ata_device *dev;
+};

Field names are usually indented. It would be nice to have a comment

checkscript.sh doesn't seem like this if I put a tab around the ':'

ERROR: spaces prohibited around that ':' (ctx:VxW) #222: FILE: include/uapi/linux/cdrom.h:915:

(quoted diff) +1 -0

+	__u8 reserved1:		2;
 	              ^

Quoted 1 line

Which style should I follow?

struct zpodd {
	bool			slot:1;
	bool			drawer:1;

	struct ata_device	*dev;
};

Quoted 7 lines

Quoted 3 lines

explaining synchronization. Bitfields w/ their implicit RMW ops tend to make people wonder about what the access rules are.

The slot and drawer bit field is assigned only once during ata probe time in EH context, and accessed later in PM's callback context. Not sure what access rule should I describe...

/* init during probe, RO afterwards */ should do but I'd prefer if you stay away from bitfields altogether. There are cases where bitfields are okay but when you're working across multiple locking domains, it usually is a bad idea because the code which accesses those fields look completely independent while still being able to interact with each other. They look properly synchronized until you realized they live on the same machine word.

Quoted 7 lines

Quoted 7 lines

Quoted 6 lines

+/*
+ * Per the spec, only slot type and drawer type ODD can be supported
+ *
+ * Return 0 for slot type, 1 for drawer, -ENODEV for other types or on error.
+ */

Quoted 5 lines

Quoted 1 line

Maybe bool odd_has_drawer() is better?

There are other types of ODD other than slot and drawer, and both slot and drawer type ODDs can be supported for ZPODD. So a bool can't convey such information :-)

Then please make it a proper ATA enum and use it in struct zpodd too.

drivers/ata/libata-zpodd.c +14 -0

+/* Check zero power ready status */
+void zpodd_on_suspend(struct ata_device *dev)
+{
+	struct zpodd *zpodd = dev->zpodd;
+	unsigned long expires;
+
+	if (!zpready(dev)) {
+		zpodd->zp_ready = false;
+		zpodd->last_ready = 0;
+		return;
+	}
+
+	if (!zpodd->last_ready) {
+		zpodd->last_ready = jiffies;

Hello, Aaron.

Quoted 21 lines · Aaron Lu

drivers/ata/libata-zpodd.c +21 -0

+/* Check zero power ready status */
+void zpodd_on_suspend(struct ata_device *dev)
+{
+	struct zpodd *zpodd = dev->zpodd;
+	unsigned long expires;
+
+	if (!zpready(dev)) {
+		zpodd->zp_ready = false;
+		zpodd->last_ready = 0;
+		return;
+	}
+
+	if (!zpodd->last_ready) {
+		zpodd->last_ready = jiffies;
+		return;
+	}
+
+	expires = zpodd->last_ready +
+		  msecs_to_jiffies(zpodd_poweroff_delay * 1000);
+	if (time_before(jiffies, expires))
+		return;

drivers/ata/libata-zpodd.c static bool odd_can_poweroff(struct ata_device *ata_dev) · line 156

Quoted 3 lines

drivers/ata/libata-zpodd.c +3 -0

+
+	zpodd->zp_ready = true;
+}

Using 0 jiffies as special value is generally considered a bad form. It should be mostly ok here but it's not like avoiding that is difficult, so let's please not use 0 jiffies as special value. If you have to, add another variable zp_sample_cnt or whatever.

drivers/ata/libata-zpodd.c +33 -0

+bool zpodd_zpready(struct ata_device *dev)
+{
+	struct zpodd *zpodd = dev->zpodd;
+	return zpodd->zp_ready;
+}
+
+void zpodd_pre_poweroff(struct ata_device *dev)
+{
+	struct zpodd *zpodd = dev->zpodd;
+
+	zpodd->powered_off = true;
+	device_set_run_wake(&dev->sdev->sdev_gendev, true);
+	acpi_pm_device_run_wake(&dev->sdev->sdev_gendev, true);
+}
+
+void zpodd_pre_poweron(struct ata_device *dev)
+{
+	struct zpodd *zpodd = dev->zpodd;
+
+	if (zpodd->powered_off) {
+		acpi_pm_device_run_wake(&dev->sdev->sdev_gendev, false);
+		device_set_run_wake(&dev->sdev->sdev_gendev, false);
+	}
+}
+
+void zpodd_post_resume(struct ata_device *dev)
+{
+	struct zpodd *zpodd = dev->zpodd;
+
+	if (!zpodd->powered_off)
+		return;
+
+	zpodd->powered_off = false;

Quoted 39 lines · Aaron Lu

drivers/ata/libata-zpodd.c +39 -0

+bool zpodd_zpready(struct ata_device *dev)
+{
+	struct zpodd *zpodd = dev->zpodd;
+	return zpodd->zp_ready;
+}
+
+void zpodd_pre_poweroff(struct ata_device *dev)
+{
+	struct zpodd *zpodd = dev->zpodd;
+
+	zpodd->powered_off = true;
+	device_set_run_wake(&dev->sdev->sdev_gendev, true);
+	acpi_pm_device_run_wake(&dev->sdev->sdev_gendev, true);
+}
+
+void zpodd_pre_poweron(struct ata_device *dev)
+{
+	struct zpodd *zpodd = dev->zpodd;
+
+	if (zpodd->powered_off) {
+		acpi_pm_device_run_wake(&dev->sdev->sdev_gendev, false);
+		device_set_run_wake(&dev->sdev->sdev_gendev, false);
+	}
+}
+
+void zpodd_post_resume(struct ata_device *dev)
+{
+	struct zpodd *zpodd = dev->zpodd;
+
+	if (!zpodd->powered_off)
+		return;
+
+	zpodd->powered_off = false;
+
+	if (zpodd->from_notify) {
+		zpodd->from_notify = false;
+		if (zpodd->drawer)
+			eject_tray(dev);
+	}

drivers/ata/libata-zpodd.c void zpodd_on_suspend(struct ata_device *dev) · line 212

Quoted 4 lines

drivers/ata/libata-zpodd.c +4 -0

+
+	zpodd->last_ready = 0;
+	zpodd->zp_ready = false;
+}

I would really appreciate some comments at least on functions visible outside zpodd.c. Please add proper function comments explaining what they're doing to achieve what.

Expose pm qos flags to user space so that user has a chance to disable pm features like power off, if he/she has a broken platform or devices or simply does not like this pm feature.

This flag is exposed to user space only for ata device or atapi device that is zero power capable. For normal atapi device, it will never be powered off.

Signed-off-by Aaron Lu <[email protected]>

---
 drivers/ata/libata-acpi.c | 3 +++
 1 file changed, 3 insertions(+)

drivers/ata/libata-acpi.c +1 -0

index e832bf6..5b67be3 100644
@@ -17,6 +17,7 @@
 #include <linux/pci.h>
 #include <linux/slab.h>
 #include <linux/pm_runtime.h>
+#include <linux/pm_qos.h>
 #include <scsi/scsi_device.h>
 #include "libata.h"
 

Quoted 25 lines · Aaron Lu

Expose pm qos flags to user space so that user has a chance to disable pm features like power off, if he/she has a broken platform or devices or simply does not like this pm feature.

This flag is exposed to user space only for ata device or atapi device that is zero power capable. For normal atapi device, it will never be powered off.

Signed-off-by Aaron Lu <[email protected]>

---
 drivers/ata/libata-acpi.c | 3 +++
 1 file changed, 3 insertions(+)

drivers/ata/libata-acpi.c +1 -0

index e832bf6..5b67be3 100644
@@ -17,6 +17,7 @@
 #include <linux/pci.h>
 #include <linux/slab.h>
 #include <linux/pm_runtime.h>
+#include <linux/pm_qos.h>
 #include <scsi/scsi_device.h>
 #include "libata.h"
 

drivers/ata/libata-acpi.c static void ata_acpi_unregister_power_resource(struct ata_device *dev) · line 1028

Quoted 7 lines

drivers/ata/libata-acpi.c +2 -0

@@ -1022,6 +1023,8 @@ static void ata_acpi_unregister_power_resource(struct ata_device *dev)
 void ata_acpi_bind(struct ata_device *dev)
 {
 	ata_acpi_register_power_resource(dev);
+	if (dev->class == ATA_DEV_ATA || zpodd_dev_enabled(dev))
+		dev_pm_qos_expose_flags(&dev->sdev->sdev_gendev, 0);
 }

Why from ata_acpi_bind()?

When the ODD is powered off, any action the user did to the ODD that would generate a media event will trigger an ACPI interrupt, so the poll for media event is no longer necessary. And the poll will also cause a runtime status change, which will stop the ODD from staying in powered off state, so the poll should better be stopped.

But since we don't have access to the gendisk structure in LLDs, here comes the event_driven flag for scsi device. This flag serves as a capability of the device, conveyed by the LLDs to upper layer. It is set when LLDs know that this device will no longer generate any media related events, so that the check_events can simply return 0 without bothering the device, effectively silence the poll.

Signed-off-by Aaron Lu <[email protected]>

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 <[email protected]>

---
  drivers/ata/libata-core.c | 19 +++++++++++++++++++
  1 file changed, 19 insertions(+)

drivers/ata/libata-core.c +0 -0

index 65a362e..f664a90 100644

Hello.

Quoted 3 lines · Aaron Lu

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,

s/oftern/often/

Quoted 15 lines

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 <[email protected]>

---
  drivers/ata/libata-core.c | 19 +++++++++++++++++++
  1 file changed, 19 insertions(+)

drivers/ata/libata-core.c +0 -0

index 65a362e..f664a90 100644

drivers/ata/libata-core.c static int ata_port_resume(struct device *dev) · line 5413

Quoted 6 lines

drivers/ata/libata-core.c +3 -0

@@ -5408,8 +5408,27 @@ 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

Article is not needed before "few". (Same comment to the changelog.)

drivers/ata/libata-core.c static int ata_port_resume(struct device *dev) · line 5415

Quoted 2 lines

drivers/ata/libata-core.c +2 -0

+ * 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.

s/mis-function/malfunction/ perhaps? (Same in the changelog.)

MBR, Sergei

v11:
Introduce event_driven flag in scsi_device to silence the media event poll after ODD is powered off;
Removed ata layer PM QOS control, instead, simply limit ACPI state to D3_HOT when choosing state;
Make the power off delay a module param named zpodd_poweroff_delay, defaults to 30 seconds.

Hello, Aaron.

Quoted 7 lines · Aaron Lu

v11:
Introduce event_driven flag in scsi_device to silence the media event poll after ODD is powered off;
Removed ata layer PM QOS control, instead, simply limit ACPI state to D3_HOT when choosing state;
Make the power off delay a module param named zpodd_poweroff_delay, defaults to 30 seconds.

Other than the nitpicks. The series generally looks good to me.

-----Original Message-----
From: [email protected] [mailto:linux-scsi- [email protected]] On Behalf Of Aaron Lu
Sent: Sunday, January 06, 2013 10:48 AM
To: Jeff Garzik; James Bottomley; Rafael J. Wysocki; Alan Stern; Tejun Heo
Cc: Aaron Lu; Wu, Jeff; [email protected]; [email protected]; [email protected]; [email protected]; Aaron Lu
Subject: [PATCH v11 0/9] ZPODD Patches

v11:
Introduce event_driven flag in scsi_device to silence the media event poll after ODD is powered off; Removed ata layer PM QOS control, instead, simply limit ACPI state to D3_HOT when choosing state; Make the power off delay a module param named zpodd_poweroff_delay, defaults to 30 seconds.

v10:
Introduce PM_QOS_NO_POLL flag to skip calling disk's events_check callback; Do not use zero power ready hint information from event poll; Check attached device in port's runtime idle callback to decide if suspend is desired; Address various comments from Tejun Heo.

v9:
Build ZPODD as part of libata instead of another standalone module as it is tightly related to other libata files.
Identify and init ZPODD during probe time instead of after SCSI device is created as suggested by Tejun Heo.
Make use of pm qos flag to give ACPI hint when choosing ACPI state. Expose qos flag to give user control of whether power off is allowed.

This patchset used Rafael's pm-qos work:
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git pm-qos

v8:
This version is a redesign, it doesn't have much to do with previous versions. The ZPODD implementation is done almost entirely in ATA layer now, except 2 helper functions from SCSI sr driver to block disk events.

The basic idea is that, when ata port is runtime suspended, it will check if the ODD is ready to be powered off. And if yes, events is blocked and power omitted; if not, ODD's power supply remains unchanged by keeping ACPI state at D0.

Some background knowledge about ZPODD is added below v1 history log.

v7:
Re work of runtime pm of sr driver, based on ideas of Alan Stern and Oliver Neukum.

Jeff, due to the ready_to_power_off flag added, there is a small change in [PATCH v7 6/6] libata: acpi: respect may_power_off flag, please check if I can still get your ack, thanks.

v6:
When user changes may_power_off flag through sysfs entry and if device is already runtime suspended, resume resume it so that it can respect this flag next time it is runtime suspended as suggested by Alan Stern. Call scsi_autopm_get/put_device once in sr_check_events as suggested by Alan Stern.

v5:
Add may_power_off flag to scsi device.
Alan Stern suggested that I should not mess runtime suspend with runtime power off, but the current zpodd implementation made it not easy to seperate. So I re-wrote the zpodd implementation, the end result is, normal ODD can also enter runtime suspended state, but their power won't be removed.

v4:
Rebase on top of Linus' tree, due to this, the problem of a missing flag in v3 is gone; Add a new function scsi_autopm_put_device_autosuspend to first mark last busy for the device and then put autosuspend it as suggested by Oliver Neukum.
Typo fix as pointed by Sergei Shtylyov.
Check can_power_off flag before any runtime pm operations in sr.

v3:
Rebase on top of scsi-misc tree;
Add the sr related patches previously in Jeff's libata tree; Re-organize the sr patches.
A problem for now: for patch
scsi: sr: support zero power ODD(ZPODD)
I can't set a flag in libata-acpi.c since a related function is missing in scsi-misc tree. Will fix this when 3.6-rc1 released.

v2:
Bug fix for v1;
Use scsi_autopm_* in sr driver instead of pm_runtime_*;

v1:
Here are some patches to make ZPODD easier to use for end users and a fix for using ZPODD with system suspend.

Some background knowledge about ZPODD:
ODD means Optical Disc Drive.
ZPODD means Zero Power ODD, it is a mechanism to place the ODD into zero power state when the system is running at S0 system state without user's awareness.
It achieved this by ACPI and SATA device attention pin. For power off, normal ACPI control method is used to place the device into D3 cold ACPI device state, aka. device power supply omitted. For power on, when user press the eject button of a drawer type ODD or when user inserts an ODD into a slot type ODD, the device attention pin will trigger. In the current x86 implementation, this pin will connect to a GPE, and the GPE will trigger an ACPI interrupt. With our pre-registered ACPI notification code, the device can be runtime resumed, and we place the device back to full power state by setting its ACPI state to D0. The whole process is transparent to the end user.

Aaron Lu (9):
scsi: sr: support runtime pm
libata: Add CONFIG_SATA_ZPODD
libata: identify and init ZPODD devices
libata: move acpi notification code to zpodd
libata: check zero power ready status for ZPODD
libata: handle power transition of ODD
libata: expose pm qos flags for ata device
libata: no poll when ODD is powered off
libata: do not suspend port if normal ODD is attached

 drivers/ata/Kconfig        |  13 +++
 drivers/ata/Makefile       |   1 +
 drivers/ata/libata-acpi.c  | 111 +++++-------------  drivers/ata/libata-core.c  |
23 +++-
 drivers/ata/libata-eh.c    |  12 +-
 drivers/ata/libata-zpodd.c | 281
+++++++++++++++++++++++++++++++++++++++++++++
 drivers/ata/libata.h       |  27 +++++
 drivers/scsi/sr.c          |  36 +++++-
 include/linux/libata.h     |   3 +
 include/scsi/scsi_device.h |   1 +
 include/uapi/linux/cdrom.h |  34 ++++++
 11 files changed, 452 insertions(+), 90 deletions(-)  create mode 100644

drivers/ata/libata-zpodd.c

--
1.7.11.7

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Quoted 11 lines

-----Original Message-----
From: [email protected] [mailto:linux-scsi- [email protected]] On Behalf Of Aaron Lu
Sent: Sunday, January 06, 2013 10:48 AM
To: Jeff Garzik; James Bottomley; Rafael J. Wysocki; Alan Stern; Tejun Heo
Cc: Aaron Lu; Wu, Jeff; [email protected]; [email protected]; [email protected]; [email protected]; Aaron Lu
Subject: [PATCH v11 0/9] ZPODD Patches

Quoted 7 lines

v11:
Introduce event_driven flag in scsi_device to silence the media event poll after ODD is powered off; Removed ata layer PM QOS control, instead, simply limit ACPI state to D3_HOT when choosing state; Make the power off delay a module param named zpodd_poweroff_delay, defaults to 30 seconds.

1. Tray type ZPODD , test pass;
2. Slot type ZPODD , test pass;

Tested-by Jeff Wu <[email protected]>

Quoted 127 lines

v10:
Introduce PM_QOS_NO_POLL flag to skip calling disk's events_check callback; Do not use zero power ready hint information from event poll; Check attached device in port's runtime idle callback to decide if suspend is desired; Address various comments from Tejun Heo.

v9:
Build ZPODD as part of libata instead of another standalone module as it is tightly related to other libata files.
Identify and init ZPODD during probe time instead of after SCSI device is created as suggested by Tejun Heo.
Make use of pm qos flag to give ACPI hint when choosing ACPI state. Expose qos flag to give user control of whether power off is allowed.

This patchset used Rafael's pm-qos work:
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git pm-qos

v8:
This version is a redesign, it doesn't have much to do with previous versions. The ZPODD implementation is done almost entirely in ATA layer now, except 2 helper functions from SCSI sr driver to block disk events.

The basic idea is that, when ata port is runtime suspended, it will check if the ODD is ready to be powered off. And if yes, events is blocked and power omitted; if not, ODD's power supply remains unchanged by keeping ACPI state at D0.

Some background knowledge about ZPODD is added below v1 history log.

v7:
Re work of runtime pm of sr driver, based on ideas of Alan Stern and Oliver Neukum.

Jeff, due to the ready_to_power_off flag added, there is a small change in [PATCH v7 6/6] libata: acpi: respect may_power_off flag, please check if I can still get your ack, thanks.

v6:
When user changes may_power_off flag through sysfs entry and if device is already runtime suspended, resume resume it so that it can respect this flag next time it is runtime suspended as suggested by Alan Stern. Call scsi_autopm_get/put_device once in sr_check_events as suggested by Alan Stern.

v5:
Add may_power_off flag to scsi device.
Alan Stern suggested that I should not mess runtime suspend with runtime power off, but the current zpodd implementation made it not easy to seperate. So I re-wrote the zpodd implementation, the end result is, normal ODD can also enter runtime suspended state, but their power won't be removed.

v4:
Rebase on top of Linus' tree, due to this, the problem of a missing flag in v3 is gone; Add a new function scsi_autopm_put_device_autosuspend to first mark last busy for the device and then put autosuspend it as suggested by Oliver Neukum.
Typo fix as pointed by Sergei Shtylyov.
Check can_power_off flag before any runtime pm operations in sr.

v3:
Rebase on top of scsi-misc tree;
Add the sr related patches previously in Jeff's libata tree; Re-organize the sr patches.
A problem for now: for patch
scsi: sr: support zero power ODD(ZPODD)
I can't set a flag in libata-acpi.c since a related function is missing in scsi-misc tree. Will fix this when 3.6-rc1 released.

v2:
Bug fix for v1;
Use scsi_autopm_* in sr driver instead of pm_runtime_*;

v1:
Here are some patches to make ZPODD easier to use for end users and a fix for using ZPODD with system suspend.

Some background knowledge about ZPODD:
ODD means Optical Disc Drive.
ZPODD means Zero Power ODD, it is a mechanism to place the ODD into zero power state when the system is running at S0 system state without user's awareness.
It achieved this by ACPI and SATA device attention pin. For power off, normal ACPI control method is used to place the device into D3 cold ACPI device state, aka. device power supply omitted. For power on, when user press the eject button of a drawer type ODD or when user inserts an ODD into a slot type ODD, the device attention pin will trigger. In the current x86 implementation, this pin will connect to a GPE, and the GPE will trigger an ACPI interrupt. With our pre-registered ACPI notification code, the device can be runtime resumed, and we place the device back to full power state by setting its ACPI state to D0. The whole process is transparent to the end user.

Aaron Lu (9):
scsi: sr: support runtime pm
libata: Add CONFIG_SATA_ZPODD
libata: identify and init ZPODD devices
libata: move acpi notification code to zpodd
libata: check zero power ready status for ZPODD
libata: handle power transition of ODD
libata: expose pm qos flags for ata device
libata: no poll when ODD is powered off
libata: do not suspend port if normal ODD is attached

 drivers/ata/Kconfig        |  13 +++
 drivers/ata/Makefile       |   1 +
 drivers/ata/libata-acpi.c  | 111 +++++-------------  drivers/ata/libata-core.c  |
23 +++-
 drivers/ata/libata-eh.c    |  12 +-
 drivers/ata/libata-zpodd.c | 281
+++++++++++++++++++++++++++++++++++++++++++++
 drivers/ata/libata.h       |  27 +++++
 drivers/scsi/sr.c          |  36 +++++-
 include/linux/libata.h     |   3 +
 include/scsi/scsi_device.h |   1 +
 include/uapi/linux/cdrom.h |  34 ++++++
 11 files changed, 452 insertions(+), 90 deletions(-)  create mode 100644

drivers/ata/libata-zpodd.c

--
1.7.11.7

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