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From: mike <qiudayu@linux.vnet.ibm.com>
To: ying.huang@intel.com
Cc: bhelgaas@google.com, stern@rowland.harvard.edu,
	linux-pci@vger.kernel.org
Subject: A question about the patch: [PATCH] PCI/PM: Keep runtime PM enabled for unbound PCI devices
Date: Wed, 13 Nov 2013 21:09:36 +0800	[thread overview]
Message-ID: <52837A10.3040301@linux.vnet.ibm.com> (raw)

Hi Huang Ying,

I see you are the author of this patch, commit id is:
967577b062417b4e4b8e27b711220f4124f5153a

I have a question while I try to understand this patch,
So I would very grateful if you or others can give me some reply.....

............
-       rc = ddi->drv->probe(ddi->dev, ddi->id);
+       pm_runtime_get_sync(dev);
+       pci_dev->driver = pci_drv;
^^^^^^^^^^^^^^^^^^^^^^^^^^
I see here you make the driver to initialize before probe,
But I have no idea of why you do this change.....

and I look inside the code, it may be pm_runtime relate??

Thanks
Mike
+       rc = pci_drv->probe(pci_dev, ddi->id);
         if (rc) {
-               pm_runtime_disable(dev);
-               pm_runtime_set_suspended(dev);
-               pm_runtime_put_noidle(dev);
+               pci_dev->driver = NULL;
+               pm_runtime_put_sync(dev);
         }
-       if (parent)
-               pm_runtime_put(parent);
         return rc;
  }

@@ -330,10 +325,8 @@ __pci_device_probe(struct pci_driver *drv, struct 
pci_dev *pci_dev)
                 id = pci_match_device(drv, pci_dev);
                 if (id)
                         error = pci_call_probe(drv, pci_dev, id);
-               if (error >= 0) {
-                       pci_dev->driver = drv;
+               if (error >= 0)
                         error = 0;
-               }
         }
         return error;
  }
.......................


             reply	other threads:[~2013-11-13 13:09 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-11-13 13:09 mike [this message]
2013-11-13 16:47 ` A question about the patch: [PATCH] PCI/PM: Keep runtime PM enabled for unbound PCI devices Bjorn Helgaas
2013-11-13 19:20   ` Alan Stern
2013-11-14  3:23     ` mike
2013-11-14  5:59       ` Huang Ying
2013-11-14  7:19         ` mike
2013-11-14  7:53           ` Huang Ying
2013-11-14  8:12             ` mike
2013-11-14  8:25               ` Huang Ying
2013-11-14  8:37                 ` mike
2013-11-14  8:54                   ` Huang Ying
2013-11-26  5:41                     ` Mike Qiu
2013-11-26 20:32                       ` Rafael J. Wysocki
2013-11-27  5:32                         ` Mike Qiu
2013-11-27  6:31                           ` Huang Ying
2013-11-27 14:15                             ` Rafael J. Wysocki

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