On Mon, Oct 14, 2013 at 03:55:48PM +0800, Peter Chen wrote: > On Mon, Oct 14, 2013 at 10:04:58AM +0200, Lothar Waßmann wrote: > > Hi, > > > > Peter Chen wrote: > > > This commit adds runtime and system power management support for > > > chipidea core. The runtime pm support is controlled by glue > > > layer, it can be enabled by flag CI_HDRC_SUPPORTS_RUNTIME_PM. > > > > > [...] > > > +#ifdef CONFIG_PM > > > +static int ci_controller_suspend(struct device *dev) > > > +{ > > > + struct ci_hdrc *ci = dev_get_drvdata(dev); > > > + > > > + dev_dbg(dev, "at %s\n", __func__); > > > + > > > + if (atomic_read(&ci->in_lpm)) > > > + return 0; > > > + > > What does this 'atomic_read()' buy you over just testing/assinging a > > simple integer. Note that just because the function has 'atomic' in > > its name the sequence: > > atomic_read(); > > ... > > atomic_set(); > > does not magically become an atomic operation. > > I just want the read and set are atomic, not the operations > between atomic_read and atomic_set. It makes no sense to use atomic operations here. atomic types are to atomically read/modify/write variables. If all you ever do is atomic_read and atomic_set then you can use a simple bool variable. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html