Messages in this thread Patch in this message | | | Date | Mon, 5 Dec 2011 11:26:40 +0800 | Subject | Re: [PATCH 1/1] driver core: disable device's runtime pm during shutdown | From | Ming Lei <> |
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Hi,
On Mon, Dec 5, 2011 at 5:56 AM, NeilBrown <neilb@suse.de> wrote: > > Hi, > this patches causes a problem for me. > > Specifically it makes it impossible to power-down a device which uses twl4030 > for power control on an omap3 processor. > > To perform the shutdown we need to send a command over the i2c bus. > The relevant bus is called omap_i2c.1 and this is normally in suspend mode. > When a request is sent, omap_i2c_xfer uses pm_runtime_get_sync to wake it up, > performs the transfer, then calls pm_runtime_put to let it go back to sleep. > > So it is asleep when the new pm_runtime_disable() call is made, so it stays > asleep, omap_i2c_xfer cannot wake it, the transfer doesn't happen and the > system doesn't get powered off. > > So here is a device that should *not* have pm disabled at shutdown. > > So I feel this fix is a little too heavy-handed.
Maybe the device's runtime PM should not be disabled if there is no ->shutdown defined in its driver, how about the blew?
diff --git a/drivers/base/core.c b/drivers/base/core.c index d8b3d89..ca30659 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1743,14 +1743,16 @@ void device_shutdown(void) */ list_del_init(&dev->kobj.entry); spin_unlock(&devices_kset->list_lock); - /* Disable all device's runtime power management */ - pm_runtime_disable(dev);
+ /* Disable the device's runtime power management if + * it is to be shutdown*/ if (dev->bus && dev->bus->shutdown) { dev_dbg(dev, "shutdown\n"); + pm_runtime_disable(dev); dev->bus->shutdown(dev); } else if (dev->driver && dev->driver->shutdown) { dev_dbg(dev, "shutdown\n"); + pm_runtime_disable(dev); dev->driver->shutdown(dev); } put_device(dev);
> I don't fully understand the problem scenario described above but it seems to > me that if the auto-suspend timer can fire after the hardware has been shut > down, then maybe the hardware-shutdown should be disabling that timer. Maybe? > > Suggestions? > > Thanks, > NeilBrown
thanks, -- Ming Lei -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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