From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Brownell Subject: [patch 2.6.18-rc5 + pm patches] PM: update docs for writing .../power/state Date: Wed, 30 Aug 2006 14:12:48 -0700 Message-ID: <200608301412.49442.david-b@pacbell.net> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.osdl.org Errors-To: linux-pm-bounces@lists.osdl.org To: Greg KH Cc: Linux-pm mailing list List-Id: linux-pm@vger.kernel.org [ resend, goes on top of Linus' patch ] Updates to match current code: - Make writes to the /sys/devices/.../power/state files fail cleanly if the device requires the irqs-off call variants. - Fix comments describing the /sys/devices/.../power/state file writes to match the code; the last several releases have invalidated the previous text. Signed-off-by: David Brownell Index: g26/drivers/base/power/sysfs.c =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D --- g26.orig/drivers/base/power/sysfs.c 2006-08-30 09:51:42.000000000 -0700 +++ g26/drivers/base/power/sysfs.c 2006-08-30 14:09:57.000000000 -0700 @@ -11,18 +11,23 @@ * state - Control current power state of device * * show() returns the current power state of the device. '0' indicates - * the device is on. Other values (1-3) indicate the device is in a low + * the device is on. Other values (2) indicate the device is in some low * power state. * - * store() sets the current power state, which is an integer value - * between 0-3. If the device is on ('0'), and the value written is - * greater than 0, then the device is placed directly into the low-power - * state (via its driver's ->suspend() method). - * If the device is currently in a low-power state, and the value is 0, - * the device is powered back on (via the ->resume() method). - * If the device is in a low-power state, and a different low-power state - * is requested, the device is first resumed, then suspended into the new - * low-power state. + * store() sets the current power state, which is an integer valued + * 0, 2, or 3. Devices with bus.suspend_late(), or bus.resume_early() + * methods fail this operation; those methods couldn't be called. + * Otherwise, + * + * - If the recorded dev->power.power_state.event matches the + * target value, nothing is done. + * - If the recorded event code is nonzero, the device is reactivated + * by calling bus.resume() and/or class.resume(). + * - If the target value is nonzero, the device is suspended by + * calling class.suspend() and/or bus.suspend() with event code + * PM_EVENT_SUSPEND. + * + * This mechanism is DEPRECATED and should only be used for testing. */ = static ssize_t state_show(struct device * dev, struct device_attribute *at= tr, char * buf) @@ -38,6 +43,10 @@ static ssize_t state_store(struct device pm_message_t state; int error =3D -EINVAL; = + /* disallow incomplete suspend sequences */ + if (dev->bus && (dev->bus->suspend_late || dev->bus->resume_early)) + return error; + state.event =3D PM_EVENT_SUSPEND; /* Older apps expected to write "3" here - confused with PCI D3 */ if ((n =3D=3D 1) && !strcmp(buf, "3"))