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PCI: pciehp: Do not clear Presence Detect Changed during initialization

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It is possible that the hotplug event has already happened before the
driver is attached to a PCIe hotplug downstream port. If we just clear the
status we never get the hotplug interrupt and thus the event will be
missed.

To make sure that does not happen, we leave Presence Detect Changed bit
untouched during initialization. Then once the event is unmasked we get an
interrupt and handle the hotplug event properly.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Mika Westerberg 2017-10-13 21:35:47 +03:00 committed by Bjorn Helgaas
parent 499022396a
commit db63d40017
1 changed files with 8 additions and 3 deletions
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11
drivers/pci/hotplug/pciehp_hpc.c
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@ -858,11 +858,16 @@ struct controller *pcie_init(struct pcie_device *dev)
if (link_cap & PCI_EXP_LNKCAP_DLLLARC)
ctrl->link_active_reporting = 1;
/* Clear all remaining event bits in Slot Status register */
/*
* Clear all remaining event bits in Slot Status register except
* Presence Detect Changed. We want to make sure possible
* hotplug event is triggered when the interrupt is unmasked so
* that we don't lose that event.
*/
pcie_capability_write_word(pdev, PCI_EXP_SLTSTA,
PCI_EXP_SLTSTA_ABP | PCI_EXP_SLTSTA_PFD |
PCI_EXP_SLTSTA_MRLSC | PCI_EXP_SLTSTA_PDC |
PCI_EXP_SLTSTA_CC | PCI_EXP_SLTSTA_DLLSC);
PCI_EXP_SLTSTA_MRLSC | PCI_EXP_SLTSTA_CC |
PCI_EXP_SLTSTA_DLLSC);
ctrl_info(ctrl, "Slot #%d AttnBtn%c PwrCtrl%c MRL%c AttnInd%c PwrInd%c HotPlug%c Surprise%c Interlock%c NoCompl%c LLActRep%c\n",
(slot_cap & PCI_EXP_SLTCAP_PSN) >> 19,