On Sat, Jan 19, 2013 at 01:11:45PM -0500, Alan Stern wrote:
> On Sat, 19 Jan 2013, Aaron Lu wrote:
> > Considering ODD's use case, I was thinking of moving the
> > blk_pm_runtime_init call to sd.c, as sr will not use request based auto
> > suspend. Probably right before we decrease usage count for the device in
> > sd_probe_async. What do you think?
>
> That makes sense. But then you should review the changes in scsi_pm.c
> to make sure they will work okay for devices that aren't using
> block-layer runtime PM.
Now that we have two different runtime PM schemes for scsi device, and
I think there are two ways to make them work:
1 Do it all in scsi_pm.c. In bus' runtime PM callback, check if this
device is using block layer runtime PM API, and act accordingly;
2 Do it in indivisual drivers' runtime PM callback. Bus' runtime PM
callbacks just call pm_generic_runtime_xxx, and each driver's runtime
PM callback will need to do what is appropriate for them.
Personally I want to go with option 1, but I would like to hear your
opinion :-)
And for option 1, the code would be like this:
static int scsi_blk_runtime_suspend(struct device *dev)
{
struct scsi_device *sdev = to_scsi_device(dev);
int err;
err = blk_pre_runtime_suspend(sdev->request_queue);
if (err)
return err;
err = pm_generic_runtime_suspend(dev);
blk_post_runtime_suspend(sdev->request_queue, err);
return err;
}
static int scsi_dev_runtime_suspend(struct device *dev)
{
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
int err;
err = scsi_dev_type_suspend(dev, pm ? pm->runtime_suspend : NULL);
if (err == -EAGAIN)
pm_schedule_suspend(dev, jiffies_to_msecs(
round_jiffies_up_relative(HZ/10)));
return err;
}
static int scsi_runtime_suspend(struct device *dev)
{
int err = 0;
dev_dbg(dev, "scsi_runtime_suspend\n");
if (scsi_is_sdev_device(dev)) {
struct scsi_device *sdev = to_scsi_device(dev);
if (sdev->request_queue->dev)
err = scsi_blk_runtime_suspend(dev);
else
err = scsi_dev_runtime_suspend(dev);
}
/* Insert hooks here for targets, hosts, and transport classes */
return err;
}
static int scsi_blk_runtime_resume(struct device *dev)
{
struct scsi_device *sdev = to_scsi_device(dev);
int err;
blk_pre_runtime_resume(sdev->request_queue);
err = pm_generic_runtime_resume(dev);
blk_post_runtime_resume(sdev->request_queue, err);
return err;
}
static int scsi_dev_runtime_resume(struct device *dev)
{
const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
return scsi_dev_type_resume(dev, pm ? pm->runtime_resume : NULL);
}
static int scsi_runtime_resume(struct device *dev)
{
int err = 0;
dev_dbg(dev, "scsi_runtime_resume\n");
if (scsi_is_sdev_device(dev)) {
struct scsi_device *sdev = to_scsi_device(dev);
if (sdev->request_queue->dev)
err = scsi_blk_runtime_resume(dev);
else
err = scsi_dev_runtime_resume(dev);
}
/* Insert hooks here for targets, hosts, and transport classes */
return err;
}
static int scsi_runtime_idle(struct device *dev)
{
int err;
dev_dbg(dev, "scsi_runtime_idle\n");
/* Insert hooks here for targets, hosts, and transport classes */
if (scsi_is_sdev_device(dev)) {
struct scsi_device *sdev = to_scsi_device(dev);
if (sdev->request_queue->dev) {
pm_runtime_mark_last_busy(dev);
err = pm_runtime_autosuspend(dev);
} else {
err = pm_schedule_suspend(dev, 100);
}
} else {
err = pm_runtime_suspend(dev);
}
return err;
}
Please feel free to suggest, thanks.
-Aaron
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