In case user's system is broken with ZPODD(either platform or device), we use this flag to let user disable ZPODD.
A sysfs entry may_power_off is used as the interface to show/store the scsi device's may_power_off flag. If 0, we will disable ZPODD; If 1, we will re-enable ZPODD. The sysfs entry for may_power_off only appears for those ZPODD capable system(platform + device), and may_power_off implies can_power_off. By default, we set may_power_off to 1. Signed-off-by: Aaron Lu <[email protected]> --- drivers/scsi/sr.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 49 insertions(+), 6 deletions(-) diff --git a/drivers/scsi/sr.c b/drivers/scsi/sr.c index e6e5549..bc9df62 100644 --- a/drivers/scsi/sr.c +++ b/drivers/scsi/sr.c @@ -158,7 +158,7 @@ static inline struct scsi_cd *scsi_cd_get(struct gendisk *disk) kref_get(&cd->kref); if (scsi_device_get(cd->device)) goto out_put; - if (cd->device->can_power_off && scsi_autopm_get_device(cd->device)) + if (scsi_autopm_get_device(cd->device)) goto out_pm; goto out; @@ -179,11 +179,50 @@ static void scsi_cd_put(struct scsi_cd *cd) mutex_lock(&sr_ref_mutex); kref_put(&cd->kref, sr_kref_release); scsi_device_put(sdev); - if (sdev->can_power_off) - scsi_autopm_put_device_autosuspend(sdev); + scsi_autopm_put_device_autosuspend(sdev); mutex_unlock(&sr_ref_mutex); } +static ssize_t +may_power_off_show(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct scsi_device *sdev = to_scsi_device(dev); + return snprintf(buf, 10, "%d\n", sdev->may_power_off); +} + +static ssize_t +may_power_off_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count) +{ + int value = -EINVAL; + struct scsi_device *sdev = to_scsi_device(dev); + struct scsi_cd *cd = dev_get_drvdata(dev); + + if (buf[1] == '\0' || (buf[1] == '\n' && buf[2] == '\0')) { + if (buf[0] == '1') + value = 1; + else if (buf[0] == '0') + value = 0; + } + + if (value >= 0) { + if (sdev->may_power_off != value) { + if (value == 0) { + if (!atomic_dec_and_test(&cd->suspend_count)) + scsi_autopm_get_device(cd->device); + } else + atomic_set(&cd->suspend_count, 1); + sdev->may_power_off = value; + } + value = count; + } + + return value; +} +DEVICE_ATTR(may_power_off, S_IRUGO | S_IWUSR, + may_power_off_show, may_power_off_store); + static int sr_suspend(struct device *dev, pm_message_t msg) { int poweroff; @@ -342,7 +381,7 @@ static unsigned int sr_check_events(struct cdrom_device_info *cdi, return 0; /* if the logical unit just finished loading/unloading, do a TUR */ - if (cd->device->can_power_off && cd->dbml && sr_unit_load_done(cd)) { + if (cd->device->may_power_off && cd->dbml && sr_unit_load_done(cd)) { events = 0; goto do_tur; } @@ -396,7 +435,7 @@ do_tur: cd->tur_changed = true; } - if (cd->device->can_power_off && !cd->media_present) { + if (cd->device->may_power_off && !cd->media_present) { if (cd->cdi.mask & CDC_CLOSE_TRAY) poweroff = 1; else @@ -850,6 +889,8 @@ static int sr_probe(struct device *dev) pm_runtime_set_autosuspend_delay(dev, 180 * 1000); pm_runtime_use_autosuspend(dev); atomic_set(&cd->suspend_count, 1); + sdev->may_power_off = 1; + device_create_file(dev, &dev_attr_may_power_off); } disk->driverfs_dev = &sdev->sdev_gendev; @@ -1138,10 +1179,12 @@ static int sr_remove(struct device *dev) struct scsi_cd *cd = dev_get_drvdata(dev); /* disable runtime pm and possibly resume the device */ - if (cd->device->can_power_off && + if (cd->device->may_power_off && !atomic_dec_and_test(&cd->suspend_count)) scsi_autopm_get_device(cd->device); + device_remove_file(dev, &dev_attr_may_power_off); + blk_queue_prep_rq(cd->device->request_queue, scsi_prep_fn); del_gendisk(cd->disk); -- 1.7.11.5 -- 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
