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* [PATCH] enclosure: add support for enclosure services
@ 2008-02-03 21:40 James Bottomley
  2008-02-03 22:03 ` Sam Ravnborg
  2008-02-05  0:32 ` Luben Tuikov
  0 siblings, 2 replies; 31+ messages in thread
From: James Bottomley @ 2008-02-03 21:40 UTC (permalink / raw)
  To: linux-scsi; +Cc: linux-kernel, linux-ide, Accardi, Kristen C

The enclosure misc device is really just a library providing sysfs
support for physical enclosure devices and their components.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
---

See the additional ses patch for SCSI enclosure services users of this.

---
 drivers/misc/Kconfig      |   10 +
 drivers/misc/Makefile     |    1 +
 drivers/misc/enclosure.c  |  449 +++++++++++++++++++++++++++++++++++++++++++++
 include/linux/enclosure.h |  120 ++++++++++++
 4 files changed, 580 insertions(+), 0 deletions(-)
 create mode 100644 drivers/misc/enclosure.c
 create mode 100644 include/linux/enclosure.h

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index b5e67c0..c6e5c09 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -11,6 +11,7 @@ menuconfig MISC_DEVICES
 
 	  If you say N, all options in this submenu will be skipped and disabled.
 
+
 if MISC_DEVICES
 
 config IBM_ASM
@@ -232,4 +233,13 @@ config ATMEL_SSC
 
 	  If unsure, say N.
 
+config ENCLOSURE_SERVICES
+	tristate "Enclosure Services"
+	default n
+	help
+	  Provides support for intelligent enclosures (bays which
+	  contain storage devices).  You also need either a host
+	  driver (SCSI/ATA) which supports enclosures
+	  or a SCSI enclosure device (SES) to use these services.
+
 endif # MISC_DEVICES
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 87f2685..de9f1f5 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -17,3 +17,4 @@ obj-$(CONFIG_SONY_LAPTOP)	+= sony-laptop.o
 obj-$(CONFIG_THINKPAD_ACPI)	+= thinkpad_acpi.o
 obj-$(CONFIG_FUJITSU_LAPTOP)	+= fujitsu-laptop.o
 obj-$(CONFIG_EEPROM_93CX6)	+= eeprom_93cx6.o
+obj-$(CONFIG_ENCLOSURE_SERVICES) += enclosure.o
\ No newline at end of file
diff --git a/drivers/misc/enclosure.c b/drivers/misc/enclosure.c
new file mode 100644
index 0000000..e4683cd
--- /dev/null
+++ b/drivers/misc/enclosure.c
@@ -0,0 +1,449 @@
+/*
+ * Enclosure Services
+ *
+ * Copyright (C) 2008 James Bottomley <James.Bottomley@HansenPartnership.com>
+ *
+**-----------------------------------------------------------------------------
+**
+**  This program is free software; you can redistribute it and/or
+**  modify it under the terms of the GNU General Public License
+**  version 2 as published by the Free Software Foundation.
+**
+**  This program is distributed in the hope that it will be useful,
+**  but WITHOUT ANY WARRANTY; without even the implied warranty of
+**  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+**  GNU General Public License for more details.
+**
+**  You should have received a copy of the GNU General Public License
+**  along with this program; if not, write to the Free Software
+**  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+**
+**-----------------------------------------------------------------------------
+*/
+#include <linux/device.h>
+#include <linux/enclosure.h>
+#include <linux/err.h>
+#include <linux/list.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+
+static LIST_HEAD(container_list);
+static DEFINE_MUTEX(container_list_lock);
+static struct class enclosure_class;
+static struct class enclosure_component_class;
+
+/**
+ * enclosure_find - find an enclosure given a device
+ * @dev:	the device to find for
+ *
+ * Looks through the list of registered enclosures to see
+ * if it can find a match for a device.  Returns NULL if no
+ * enclosure is found.
+ */
+struct enclosure_device *enclosure_find(struct device *dev)
+{
+	struct enclosure_device *edev = NULL;
+
+	mutex_lock(&container_list_lock);
+	list_for_each_entry(edev, &container_list, node) {
+		if (edev->cdev.dev == dev) {
+			mutex_unlock(&container_list_lock);
+			return edev;
+		}
+	}
+	mutex_unlock(&container_list_lock);
+
+	return NULL;
+}
+EXPORT_SYMBOL(enclosure_find);
+
+/**
+ * enclosure_for_each_device - calls a function for each enclosure
+ * @fn:		the function to call
+ * @data:	the data to pass to each call
+ *
+ * Loops over all the enclosures calling the function.
+ *
+ * Note, this function uses a mutex which will be held across calls to
+ * @fn, so it must have user context, and @fn should not sleep or
+ * otherwise cause the mutex to be held for indefinite periods
+ */
+int enclosure_for_each_device(int (*fn)(struct enclosure_device *, void *),
+			      void *data)
+{
+	int error = 0;
+	struct enclosure_device *edev;
+
+	mutex_lock(&container_list_lock);
+	list_for_each_entry(edev, &container_list, node) {
+		error = fn(edev, data);
+		if (error)
+			break;
+	}
+	mutex_unlock(&container_list_lock);
+
+	return error;
+}
+EXPORT_SYMBOL_GPL(enclosure_for_each_device);
+
+/**
+ * enclosure_register - register device as an enclosure
+ *
+ * @dev:	device containing the enclosure
+ * @components:	number of components in the enclosure
+ *
+ * This sets up the device for being an enclosure.  Note that @dev does
+ * not have to be a dedicated enclosure device.  It may be some other type
+ * of device that additionally responds to enclosure services
+ */
+struct enclosure_device *
+enclosure_register(struct device *dev, const char *name, int components,
+		   struct enclosure_component_callbacks *cb)
+{
+	struct enclosure_device *edev =
+		kzalloc(sizeof(struct enclosure_device) +
+			sizeof(struct enclosure_component)*components,
+			GFP_KERNEL);
+	int err, i;
+
+	if (!edev)
+		return ERR_PTR(-ENOMEM);
+
+	if (!cb)
+		return ERR_PTR(-EINVAL);
+
+	edev->components = components;
+
+	edev->cdev.class = &enclosure_class;
+	edev->cdev.dev = get_device(dev);
+	edev->cb = cb;
+	snprintf(edev->cdev.class_id, BUS_ID_SIZE, "%s", name);
+	err = class_device_register(&edev->cdev);
+	if (err)
+		goto err;
+
+	for (i = 0; i < components; i++)
+		edev->component[i].number = -1;
+
+	mutex_lock(&container_list_lock);
+	list_add_tail(&edev->node, &container_list);
+	mutex_unlock(&container_list_lock);
+
+	return edev;
+
+ err:
+	put_device(edev->cdev.dev);
+	kfree(edev);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(enclosure_register);
+
+static struct enclosure_component_callbacks enclosure_null_callbacks;
+
+/**
+ * enclosure_unregister - remove an enclosure
+ *
+ * @edev:	the registered enclosure to remove;
+ */
+void enclosure_unregister(struct enclosure_device *edev)
+{
+	int i;
+
+	if (!edev)
+		return;
+
+	mutex_lock(&container_list_lock);
+	list_del(&edev->node);
+	mutex_unlock(&container_list_lock);
+
+	for (i = 0; i < edev->components; i++)
+		if (edev->component[i].number != -1)
+			class_device_unregister(&edev->component[i].cdev);
+
+	/* prevent any callbacks into service user */
+	edev->cb = &enclosure_null_callbacks;
+	class_device_unregister(&edev->cdev);
+}
+EXPORT_SYMBOL_GPL(enclosure_unregister);
+
+static void enclosure_release(struct class_device *cdev)
+{
+	struct enclosure_device *edev = to_enclosure_device(cdev);
+
+	put_device(cdev->dev);
+	kfree(edev);
+}
+
+static void enclosure_component_release(struct class_device *cdev)
+{
+	if (cdev->dev)
+		put_device(cdev->dev);
+	class_device_put(cdev->parent);
+}
+
+struct enclosure_component *
+enclosure_component_register(struct enclosure_device *edev,
+			     unsigned int number,
+			     enum enclosure_component_type type,
+			     const char *name)
+{
+	struct enclosure_component *ecomp;
+	struct class_device *cdev;
+	int err;
+
+	if (!edev || number >= edev->components)
+		return ERR_PTR(-EINVAL);
+
+	ecomp = &edev->component[number];
+
+	if (ecomp->number != -1)
+		return ERR_PTR(-EINVAL);
+
+	ecomp->type = type;
+	ecomp->number = number;
+	cdev = &ecomp->cdev;
+	cdev->parent = class_device_get(&edev->cdev);
+	cdev->class = &enclosure_component_class;
+	if (name)
+		snprintf(cdev->class_id, BUS_ID_SIZE, "%s", name);
+	else
+		snprintf(cdev->class_id, BUS_ID_SIZE, "%d", number);
+
+	err = class_device_register(cdev);
+	if (err)
+		ERR_PTR(err);
+
+	return ecomp;
+}
+EXPORT_SYMBOL_GPL(enclosure_component_register);
+
+int enclosure_add_device(struct enclosure_device *edev, int component,
+			 struct device *dev)
+{
+	struct class_device *cdev;
+
+	if (!edev || component >= edev->components)
+		return -EINVAL;
+
+	cdev = &edev->component[component].cdev;
+
+	class_device_del(cdev);
+	if (cdev->dev)
+		put_device(cdev->dev);
+	cdev->dev = get_device(dev);
+	return class_device_add(cdev);
+}
+EXPORT_SYMBOL_GPL(enclosure_add_device);
+
+int enclosure_remove_device(struct enclosure_device *edev, int component)
+{
+	struct class_device *cdev;
+
+	if (!edev || component >= edev->components)
+		return -EINVAL;
+
+	cdev = &edev->component[component].cdev;
+
+	class_device_del(cdev);
+	if (cdev->dev)
+		put_device(cdev->dev);
+	cdev->dev = NULL;
+	return class_device_add(cdev);
+}
+EXPORT_SYMBOL_GPL(enclosure_remove_device);
+
+/*
+ * sysfs pieces below
+ */
+
+static ssize_t enclosure_show_components(struct class_device *cdev, char *buf)
+{
+	struct enclosure_device *edev = to_enclosure_device(cdev);
+
+	return snprintf(buf, 40, "%d\n", edev->components);
+}
+
+static struct class_device_attribute enclosure_attrs[] = {
+	__ATTR(components, S_IRUGO, enclosure_show_components, NULL),
+	__ATTR_NULL
+};
+
+static struct class enclosure_class = {
+	.name			= "enclosure",
+	.owner			= THIS_MODULE,
+	.release		= enclosure_release,
+	.class_dev_attrs	= enclosure_attrs,
+};
+
+static char *enclosure_status [] = {
+	[ENCLOSURE_STATUS_UNSUPPORTED] = "unsupported",
+	[ENCLOSURE_STATUS_OK] = "OK",
+	[ENCLOSURE_STATUS_CRITICAL] = "critical",
+	[ENCLOSURE_STATUS_NON_CRITICAL] = "non-critical",
+	[ENCLOSURE_STATUS_UNRECOVERABLE] = "unrecoverable",
+	[ENCLOSURE_STATUS_NOT_INSTALLED] = "not installed",
+	[ENCLOSURE_STATUS_UNKNOWN] = "unknown",
+	[ENCLOSURE_STATUS_UNAVAILABLE] = "unavailable",
+};
+
+static char *enclosure_type [] = {
+	[ENCLOSURE_COMPONENT_DEVICE] = "device",
+	[ENCLOSURE_COMPONENT_ARRAY_DEVICE] = "array device",
+};
+
+static ssize_t get_component_fault(struct class_device *cdev, char *buf)
+{
+	struct enclosure_device *edev = to_enclosure_device(cdev->parent);
+	struct enclosure_component *ecomp = to_enclosure_component(cdev);
+
+	if (edev->cb->get_fault)
+		edev->cb->get_fault(edev, ecomp);
+	return snprintf(buf, 40, "%d\n", ecomp->fault);
+}
+
+static ssize_t set_component_fault(struct class_device *cdev, const char *buf,
+				   size_t count)
+{
+	struct enclosure_device *edev = to_enclosure_device(cdev->parent);
+	struct enclosure_component *ecomp = to_enclosure_component(cdev);
+	int val = simple_strtoul(buf, NULL, 0);
+
+	if (edev->cb->set_fault)
+		edev->cb->set_fault(edev, ecomp, val);
+	return count;
+}
+
+static ssize_t get_component_status(struct class_device *cdev, char *buf)
+{
+	struct enclosure_device *edev = to_enclosure_device(cdev->parent);
+	struct enclosure_component *ecomp = to_enclosure_component(cdev);
+
+	if (edev->cb->get_status)
+		edev->cb->get_status(edev, ecomp);
+	return snprintf(buf, 40, "%s\n", enclosure_status[ecomp->status]);
+}
+
+static ssize_t set_component_status(struct class_device *cdev, const char *buf,
+				   size_t count)
+{
+	struct enclosure_device *edev = to_enclosure_device(cdev->parent);
+	struct enclosure_component *ecomp = to_enclosure_component(cdev);
+	int i;
+
+	for (i = 0; enclosure_status[i]; i++) {
+		if (strncmp(buf, enclosure_status[i],
+			    strlen(enclosure_status[i])) == 0 &&
+		    buf[strlen(enclosure_status[i])] == '\n')
+			break;
+	}
+
+	if (enclosure_status[i] && edev->cb->set_status) {
+		edev->cb->set_status(edev, ecomp, i);
+		return count;
+	} else
+		return -EINVAL;
+}
+
+static ssize_t get_component_active(struct class_device *cdev, char *buf)
+{
+	struct enclosure_device *edev = to_enclosure_device(cdev->parent);
+	struct enclosure_component *ecomp = to_enclosure_component(cdev);
+
+	if (edev->cb->get_active)
+		edev->cb->get_active(edev, ecomp);
+	return snprintf(buf, 40, "%d\n", ecomp->active);
+}
+
+static ssize_t set_component_active(struct class_device *cdev, const char *buf,
+				   size_t count)
+{
+	struct enclosure_device *edev = to_enclosure_device(cdev->parent);
+	struct enclosure_component *ecomp = to_enclosure_component(cdev);
+	int val = simple_strtoul(buf, NULL, 0);
+
+	if (edev->cb->set_active)
+		edev->cb->set_active(edev, ecomp, val);
+	return count;
+}
+
+static ssize_t get_component_locate(struct class_device *cdev, char *buf)
+{
+	struct enclosure_device *edev = to_enclosure_device(cdev->parent);
+	struct enclosure_component *ecomp = to_enclosure_component(cdev);
+
+	if (edev->cb->get_locate)
+		edev->cb->get_locate(edev, ecomp);
+	return snprintf(buf, 40, "%d\n", ecomp->locate);
+}
+
+static ssize_t set_component_locate(struct class_device *cdev, const char *buf,
+				   size_t count)
+{
+	struct enclosure_device *edev = to_enclosure_device(cdev->parent);
+	struct enclosure_component *ecomp = to_enclosure_component(cdev);
+	int val = simple_strtoul(buf, NULL, 0);
+
+	if (edev->cb->set_locate)
+		edev->cb->set_locate(edev, ecomp, val);
+	return count;
+}
+
+static ssize_t get_component_type(struct class_device *cdev, char *buf)
+{
+	struct enclosure_component *ecomp = to_enclosure_component(cdev);
+
+	return snprintf(buf, 40, "%s\n", enclosure_type[ecomp->type]);
+}
+
+
+static struct class_device_attribute enclosure_component_attrs[] = {
+	__ATTR(fault, S_IRUGO | S_IWUSR, get_component_fault,
+	       set_component_fault),
+	__ATTR(status, S_IRUGO | S_IWUSR, get_component_status,
+	       set_component_status),
+	__ATTR(active, S_IRUGO | S_IWUSR, get_component_active,
+	       set_component_active),
+	__ATTR(locate, S_IRUGO | S_IWUSR, get_component_locate,
+	       set_component_locate),
+	__ATTR(type, S_IRUGO, get_component_type, NULL),
+	__ATTR_NULL
+};
+
+static struct class enclosure_component_class =  {
+	.name			= "enclosure_component",
+	.owner			= THIS_MODULE,
+	.class_dev_attrs	= enclosure_component_attrs,
+	.release		= enclosure_component_release,
+};
+
+static int __init enclosure_init(void)
+{
+	int err;
+
+	err = class_register(&enclosure_class);
+	if (err)
+		return err;
+	err = class_register(&enclosure_component_class);
+	if (err)
+		goto err_out;
+
+	return 0;
+ err_out:
+	class_unregister(&enclosure_class);
+
+	return err;
+}
+
+static void __exit enclosure_exit(void)
+{
+	class_unregister(&enclosure_component_class);
+	class_unregister(&enclosure_class);
+}
+
+module_init(enclosure_init);
+module_exit(enclosure_exit);
+
+MODULE_AUTHOR("James Bottomley");
+MODULE_DESCRIPTION("Enclosure Services");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/enclosure.h b/include/linux/enclosure.h
new file mode 100644
index 0000000..622177a
--- /dev/null
+++ b/include/linux/enclosure.h
@@ -0,0 +1,120 @@
+/*
+ * Enclosure Services
+ *
+ * Copyright (C) 2008 James Bottomley <James.Bottomley@HansenPartnership.com>
+ *
+**-----------------------------------------------------------------------------
+**
+**  This program is free software; you can redistribute it and/or
+**  modify it under the terms of the GNU General Public License
+**  version 2 as published by the Free Software Foundation.
+**
+**  This program is distributed in the hope that it will be useful,
+**  but WITHOUT ANY WARRANTY; without even the implied warranty of
+**  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+**  GNU General Public License for more details.
+**
+**  You should have received a copy of the GNU General Public License
+**  along with this program; if not, write to the Free Software
+**  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+**
+**-----------------------------------------------------------------------------
+*/
+#ifndef _LINUX_ENCLOSURE_H_
+#define _LINUX_ENCLOSURE_H_
+
+#include <linux/device.h>
+#include <linux/list.h>
+
+/* A few generic types ... taken from ses-2 */
+enum enclosure_component_type {
+	ENCLOSURE_COMPONENT_DEVICE = 0x01,
+	ENCLOSURE_COMPONENT_ARRAY_DEVICE = 0x17,
+};
+
+/* ses-2 common element status */
+enum enclosure_status {
+	ENCLOSURE_STATUS_UNSUPPORTED = 0,
+	ENCLOSURE_STATUS_OK,
+	ENCLOSURE_STATUS_CRITICAL,
+	ENCLOSURE_STATUS_NON_CRITICAL,
+	ENCLOSURE_STATUS_UNRECOVERABLE,
+	ENCLOSURE_STATUS_NOT_INSTALLED,
+	ENCLOSURE_STATUS_UNKNOWN,
+	ENCLOSURE_STATUS_UNAVAILABLE,
+};
+
+/* SFF-8485 activity light settings */
+enum enclosure_component_setting {
+	ENCLOSURE_SETTING_DISABLED = 0,
+	ENCLOSURE_SETTING_ENABLED = 1,
+	ENCLOSURE_SETTING_BLINK_A_ON_OFF = 2,
+	ENCLOSURE_SETTING_BLINK_A_OFF_ON = 3,
+	ENCLOSURE_SETTING_BLINK_B_ON_OFF = 6,
+	ENCLOSURE_SETTING_BLINK_B_OFF_ON = 7,
+};
+
+struct enclosure_device;
+struct enclosure_component;
+struct enclosure_component_callbacks {
+	void (*get_status)(struct enclosure_device *,
+			     struct enclosure_component *);
+	int (*set_status)(struct enclosure_device *,
+			  struct enclosure_component *,
+			  enum enclosure_status);
+	void (*get_fault)(struct enclosure_device *,
+			  struct enclosure_component *);
+	int (*set_fault)(struct enclosure_device *,
+			 struct enclosure_component *,
+			 enum enclosure_component_setting);
+	void (*get_active)(struct enclosure_device *,
+			   struct enclosure_component *);
+	int (*set_active)(struct enclosure_device *,
+			  struct enclosure_component *,
+			  enum enclosure_component_setting);
+	void (*get_locate)(struct enclosure_device *,
+			   struct enclosure_component *);
+	int (*set_locate)(struct enclosure_device *,
+			  struct enclosure_component *,
+			  enum enclosure_component_setting);
+};
+
+
+struct enclosure_component {
+	void *scratch;
+	struct class_device cdev;
+	enum enclosure_component_type type;
+	int number;
+	int fault;
+	int active;
+	int locate;
+	enum enclosure_status status;
+};
+
+struct enclosure_device {
+	void *scratch;
+	struct list_head node;
+	struct class_device cdev;
+	struct enclosure_component_callbacks *cb;
+	int components;
+	struct enclosure_component component[0];
+};
+
+#define to_enclosure_device(x) container_of((x), struct enclosure_device, cdev)
+#define to_enclosure_component(x) container_of((x), struct enclosure_component, cdev)
+
+struct enclosure_device *
+enclosure_register(struct device *, const char *, int,
+		   struct enclosure_component_callbacks *);
+void enclosure_unregister(struct enclosure_device *);
+struct enclosure_component *
+enclosure_component_register(struct enclosure_device *, unsigned int,
+				 enum enclosure_component_type, const char *);
+int enclosure_add_device(struct enclosure_device *enclosure, int component,
+			 struct device *dev);
+int enclosure_remove_device(struct enclosure_device *enclosure, int component);
+struct enclosure_device *enclosure_find(struct device *dev);
+int enclosure_for_each_device(int (*fn)(struct enclosure_device *, void *),
+			      void *data);
+
+#endif /* _LINUX_ENCLOSURE_H_ */
-- 
1.5.3.8




^ permalink raw reply	[flat|nested] 31+ messages in thread
* Re: [PATCH] enclosure: add support for enclosure services
@ 2008-02-13 11:15 Luben Tuikov
  0 siblings, 0 replies; 31+ messages in thread
From: Luben Tuikov @ 2008-02-13 11:15 UTC (permalink / raw)
  To: kristen.c.accardi, James Bottomley
  Cc: linux-scsi, linux-kernel, linux-ide, jeff

--- On Tue, 2/12/08, James Bottomley James.Bottomley@HansenPartnership.com> wrote:
> > I understand what you are trying to do - I guess I
> just doubt the value
> > you've added by doing this.  I think that
> there's going to be so much
> > customization that system vendors will want to add,
> that they are going
> > to wind up adding a custom library regardless, so
> standardising those
> > few things won't buy us anything.
> 
> It depends ... if you actually have a use for the
> customisations, yes.
> If you just want the basics of who (what's in the
> enclousure), what
> (activity) and where (locate) then I think it solves your
> problem almost
> entirely.

If the kernel doesn't solve it "entirely", then it is better
off without the kernel bloat.  In fact vendors would distribute
their own user-space application(s) to provide a consistent and
complete solution(s) of their product(s) to their customer(s).

This could also be achieved via "sg_ses", which can also
control custom vendor pages if the encodings are known by the
customer (which they would be if they purchased the product).

> So, entirely as a straw horse, tell me what else your
> enclosures provide
> that I haven't listed in the four points.

You shouldn't insist on this.  It should already be clear
to you this direction isn't the vendor's preference.

>  The SES
> standards too provide
> a huge range of things that no-one ever seems to implement
> (temperature,
> power, fan speeds etc).

Vendors do use "temperature, power and fan speeds" and
in fact more features, some of them completely custom
for their product, since they end up writing the SES
device server of the enclosure themselves (for their product).
This kind of control and representation is better left to
user-space.  The kernel neither needs to represent it
nor know about it, since it is itself not using nor
controlling it.

> I think the users of enclosures fall int these categories

This statement (above) really means that the numbers below
are but merely the speculation of one person.

> 
> 85% just want to know where their device actually is (i.e.
> that sdc is
> in enclosure slot 5)
> 50% like watching the activity lights
> 30% want to be able to have a visual locate function
> 20% want a visual failure indication (the other 80% rely on
> some OS
> notification instead)
> 
> When you add up the overlapping needs, you get about 90% of
> people happy
> with the basics that the enclosure services provide.

90% doesn't make it a necessary requirement for the kernel
to have this, as well as the fact that the kernel is neither
needing this to function properly, nor using it.

> Could there be more ... sure; should there be more ... I don't think
> so ... that's what value add the user libraries can provide.

"should there be more ... I don't think so"

This decision isn't yours to make.  In fact such a decision is never
made by one person only.  This decision is made by 1) the industry,
2) the customers and 3) vendors by the pricing of their product(s).

   Luben


^ permalink raw reply	[flat|nested] 31+ messages in thread

end of thread, other threads:[~2008-02-19 18:45 UTC | newest]

Thread overview: 31+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2008-02-03 21:40 [PATCH] enclosure: add support for enclosure services James Bottomley
2008-02-03 22:03 ` Sam Ravnborg
2008-02-04  0:16   ` James Bottomley
2008-02-06  0:12     ` Andrew Morton
2008-02-06  2:57       ` James Bottomley
2008-02-05  0:32 ` Luben Tuikov
2008-02-05  0:41   ` James Bottomley
2008-02-05  2:01     ` Luben Tuikov
2008-02-05  2:14       ` James Bottomley
2008-02-05  3:28         ` Luben Tuikov
2008-02-05  4:37           ` James Bottomley
2008-02-05  5:35             ` Luben Tuikov
2008-02-05 15:01               ` James Bottomley
2008-02-05 19:33                 ` Luben Tuikov
2008-02-05 20:29                   ` James Bottomley
2008-02-05 20:39                     ` Luben Tuikov
2008-02-12 18:22       ` Kristen Carlson Accardi
2008-02-12 18:45         ` James Bottomley
2008-02-12 19:07           ` Kristen Carlson Accardi
2008-02-12 19:28             ` James Bottomley
2008-02-13 17:45               ` Kristen Carlson Accardi
2008-02-13 18:17                 ` James Bottomley
2008-02-16 12:44                 ` Pavel Machek
2008-02-13  9:48           ` Luben Tuikov
2008-02-13 14:08             ` James Smart
2008-02-13 16:04               ` James Bottomley
2008-02-13 16:22                 ` James Smart
2008-02-13 16:43                   ` James Bottomley
2008-02-13 16:49                     ` James Smart
2008-02-12 19:45         ` Luben Tuikov
2008-02-13 11:15 Luben Tuikov

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