| Message ID | 1346768680-7287-6-git-send-email-aaron.lwe@gmail.com (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Tuesday 04 September 2012 22:24:38 Aaron Lu wrote: > From: Aaron Lu <aaron.lu@intel.com> > > Add a new flag may_power_off for scsi device, it gives the user a chance > to control when the device is runtime suspended, can we remove its power > if possible. > > And if the device can be powered off(reflected by can_power_off flag, > determined by individual driver), create a sysfs entry named > may_power_off to let user control the flag. Do we really need yet another interface to user space? Regards Oliver -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, Sep 04, 2012 at 06:01:22PM +0200, Oliver Neukum wrote: > On Tuesday 04 September 2012 22:24:38 Aaron Lu wrote: > > From: Aaron Lu <aaron.lu@intel.com> > > > > Add a new flag may_power_off for scsi device, it gives the user a chance > > to control when the device is runtime suspended, can we remove its power > > if possible. > > > > And if the device can be powered off(reflected by can_power_off flag, > > determined by individual driver), create a sysfs entry named > > may_power_off to let user control the flag. > > Do we really need yet another interface to user space? We do not have a way to let user decide when device is runtime suspended, can we remove its power, so I added this flag. PCI subsystem has a similar flag named d3cold_allowed. This flag can disable the power off of ZPODD capable devices, or put a rotational disk into powered off if user so choose. Thanks, Aaron -- To unsubscribe from this list: send the line "unsubscribe linux-pm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c index 093d4f6..8c8efd3 100644 --- a/drivers/scsi/scsi_sysfs.c +++ b/drivers/scsi/scsi_sysfs.c @@ -509,6 +509,7 @@ sdev_store_##field (struct device *dev, struct device_attribute *attr, \ return ret; \ } \ static DEVICE_ATTR(field, S_IRUGO | S_IWUSR, sdev_show_##field, sdev_store_##field); +#endif /* * scsi_sdev_check_buf_bit: return 0 if buf is "0", return 1 if buf is "1", @@ -526,7 +527,7 @@ static int scsi_sdev_check_buf_bit(const char *buf) } else return -EINVAL; } -#endif + /* * Create the actual show/store functions and data structures. */ @@ -860,6 +861,37 @@ static struct device_attribute sdev_attr_queue_type_rw = __ATTR(queue_type, S_IRUGO | S_IWUSR, show_queue_type_field, sdev_store_queue_type_rw); +static ssize_t +sdev_show_may_power_off(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct scsi_device *sdev; + sdev = to_scsi_device(dev); + return snprintf (buf, 20, "%d\n", sdev->may_power_off); +} + +static ssize_t +sdev_store_may_power_off(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + int ret; + struct scsi_device *sdev; + + ret = scsi_sdev_check_buf_bit(buf); + if (ret >= 0) { + sdev = to_scsi_device(dev); + if (sdev->may_power_off != ret) { + sdev->may_power_off = ret; + if (pm_runtime_suspended(dev)) + pm_runtime_resume(dev); + } + ret = count; + } + return ret; +} +static DEVICE_ATTR(may_power_off, S_IRUGO | S_IWUSR, + sdev_show_may_power_off, sdev_store_may_power_off); + /** * scsi_sysfs_add_sdev - add scsi device to sysfs * @sdev: scsi_device to add @@ -950,6 +982,9 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev) } } + if (sdev->can_power_off) + device_create_file(&sdev->sdev_gendev, &dev_attr_may_power_off); + return error; } diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h index 72d946f..41cec7f 100644 --- a/include/scsi/scsi_device.h +++ b/include/scsi/scsi_device.h @@ -157,6 +157,7 @@ struct scsi_device { unsigned can_power_off:1; /* Device supports runtime power off */ unsigned wce_default_on:1; /* Cache is ON by default */ unsigned wakeup_by_user:1; /* User wakes up the device */ + unsigned may_power_off:1; /* Power off is allowed by user */ DECLARE_BITMAP(supported_events, SDEV_EVT_MAXBITS); /* supported events */ struct list_head event_list; /* asserted events */