Messages in this thread | | | Date | Tue, 29 Jan 2013 10:45:18 +0400 | From | Konstantin Khlebnikov <> | Subject | Re: [PATCH 2/5] e1000e: fix pci device enable counter balance |
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Bjorn Helgaas wrote: > [+cc Rafael @sisk.pl] > > On Mon, Jan 28, 2013 at 4:09 PM, Bjorn Helgaas<bhelgaas@google.com> wrote: >> [+cc Rafael] >> >> On Fri, Jan 18, 2013 at 4:42 AM, Konstantin Khlebnikov >> <khlebnikov@openvz.org> wrote: >>> __e1000_shutdown() calls pci_disable_device() at the end, thus __e1000_resume() >>> should call pci_enable_device_mem() to keep enable counter in balance. >>> >>> Bug was introduced in commit 23606cf5d1192c2b17912cb2ef6e62f9b11de133 >>> ("e1000e / PCI / PM: Add basic runtime PM support (rev. 4)") in v2.6.35 >>> >>> Signed-off-by: Konstantin Khlebnikov<khlebnikov@openvz.org> >>> Cc: e1000-devel@lists.sourceforge.net >>> Cc: Jeff Kirsher<jeffrey.t.kirsher@intel.com> >>> Cc: Bruce Allan<bruce.w.allan@intel.com> >>> --- >>> drivers/net/ethernet/intel/e1000e/netdev.c | 7 +++++++ >>> 1 file changed, 7 insertions(+) >>> >>> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c >>> index 2853c11..6bce796 100644 >>> --- a/drivers/net/ethernet/intel/e1000e/netdev.c >>> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c >>> @@ -5598,6 +5598,13 @@ static int __e1000_resume(struct pci_dev *pdev) >>> pci_restore_state(pdev); >>> pci_save_state(pdev); >>> >>> + err = pci_enable_device_mem(pdev); >>> + if (err) { >>> + dev_err(&pdev->dev, >>> + "Cannot re-enable PCI device after suspend.\n"); >>> + return err; >>> + } >> >> Reviewed-by: Bjorn Helgaas<bhelgaas@google.com> >> >> Seems right to me, and the other users I looked at (igb, azx, >> virtio_pci) call pci_disable_device() in .suspend() and call >> pci_enable_device() in .resume() as you propose to do here. >> >> I assume the e1000 folks will handle this patch (and the previous one). >> >>> + >>> e1000e_set_interrupt_capability(adapter); >>> if (netif_running(netdev)) { >>> err = e1000_request_irq(adapter); >>> > > I'm still missing something. In your original report > (https://lkml.org/lkml/2013/1/1/25), you noticed that "enable_cnt == > 0" immediately after boot, after e1000e had claimed the device:
Yep, it rise counter from 0 to 1, and runtime-suspend immediately decrease it back to 0.
> >> Right after boot it looks like this: >> >> root@zurg:/sys/bus/pci/devices# lspci >> ... >> 00:19.0 Ethernet controller: Intel Corporation 82579LM Gigabit Network Connection (rev 04) >> ... >> root@zurg:/sys/bus/pci/devices# cat 0000\:00\:19.0/enable >> 0 >> here must be '1', not '0' > > But these patches only change the e1000e suspend/resume path. How > could they change the enable_cnt before you've even done a suspend?
suspend/resume and runtime_suspend/runtime_resume callbacks calls the one set of functions: __e1000_shutdown() / __e1000_resume()
Any suspend-resume cycle breaks enable_ent balance. Thus right after boot and first runtime-suspend device cannot wake up due to first sort of bugs and after first s2ram suspend-resume cycle driver breaks it's enable_cnt and device no longer can sleep due to second sort of bugs.
> > Bjorn
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