Re: Subject : [ PATCH ] pci-reset-error_state-to-pci_channel_io_normal-at-report_slot_reset

From: Bjorn Helgaas
Date: Mon May 20 2013 - 13:21:46 EST


On Fri, May 17, 2013 at 5:56 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote:
> On Friday, May 17, 2013 05:43:33 PM Bjorn Helgaas wrote:
>> On Fri, Apr 26, 2013 at 12:28 AM, Zhang, LongX <longx.zhang@xxxxxxxxx> wrote:

>> > + /* restore cfg space for possible link reset at upstream */
>> > + dev->state_saved = true;
>>
>> "dev->state_saved == true" means that the dev->saved_config_space
>> contains valid data. Why do we know that's the case here? I see that
>> pcie_portdrv_probe() calls pci_save_state() when we first claim the
>> port, and I guess we're assuming the state saved then is still valid.
>> But why do we need to actually set dev->state_saved here? Shouldn't
>> it be already set to true anyway?
>
> This is a dirty trick to make pci_restore_state(dev) always work here
> (because it checks dev->state_saved and does nothing if it isn't set).
> I suppose.

Yes, I did investigate enough to see that this is a dirty trick. My
question is how we know it's safe to do this dirty trick.

>> > + pci_restore_state(dev);
>> > + pcie_portdrv_restore_config(dev);
>> > + pci_enable_pcie_error_reporting(dev);
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