Re: [PATCH] net: fec: turn on device when extracting statistics

From: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Date: Mon, 28 Nov 2016 10:06:31 +0300

28.11.2016 04:29, David Miller пишет:

quoted

From: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Date: Fri, 25 Nov 2016 13:02:00 +0300

quoted

+	int i, ret;
+
+	ret = pm_runtime_get_sync(&fep->pdev->dev);
+	if (IS_ERR_VALUE(ret)) {
+		memset(data, 0, sizeof(*data) * ARRAY_SIZE(fec_stats));
+		return;
+	}

This really isn't the way to do this.

When the device is suspended and the clocks are going to be stopped,
you must fetch the statistic values into a software copy and provide
those if the device is suspended when statistics are requested.

Ok, can do that, although can't see what's wrong with waking device
here. The situation of requesting stats on down device isn't something
widely used, thus keeping handling of that as local as possible looks
better for me.

The issue is the fact that you need error handling at all and might
therefore provide a set of zero stats to the user when that entire
possibility could have been avoided in the first place by recording
the stats at suspend time.