From: Bjorn Helgaas <helgaas@kernel.org>
To: linux-pci@vger.kernel.org
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Keith Busch <keith.busch@intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"Rafael J . Wysocki" <rjw@rjwysocki.net>,
Mika Westerberg <mika.westerberg@linux.intel.com>,
linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
Bjorn Helgaas <bhelgaas@google.com>
Subject: [PATCH 3/5] PCI / PM: Check for error when reading PME status
Date: Mon, 5 Aug 2019 15:52:12 -0500 [thread overview]
Message-ID: <20190805205214.194981-4-helgaas@kernel.org> (raw)
In-Reply-To: <20190805205214.194981-1-helgaas@kernel.org>
From: Bjorn Helgaas <bhelgaas@google.com>
pci_check_pme_status() reads the Power Management capability to determine
whether a device has generated a PME. The capability is in config space,
which is accessible in D0, D1, D2, and D3hot, but not in D3cold.
If we call pci_check_pme_status() on a device that's in D3cold, config
reads fail and return ~0 data, which we erroneously interpreted as "the
device has generated a PME".
000dd5316e1c ("PCI: Do not poll for PME if the device is in D3cold")
avoided many of these problems by avoiding pci_check_pme_status() if we
think the device is in D3cold. However, it is not a complete fix because
the device may go to D3cold after we check its power state but before
pci_check_pme_status() reads the Power Management Status Register.
Return false ("device has not generated a PME") if we get an error response
reading the Power Management Status Register.
Fixes: 000dd5316e1c ("PCI: Do not poll for PME if the device is in D3cold")
Fixes: 71a83bd727cc ("PCI/PM: add runtime PM support to PCIe port")
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
---
drivers/pci/pci.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 984171d40858..af6a97d7012b 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2008,6 +2008,9 @@ bool pci_check_pme_status(struct pci_dev *dev)
pmcsr_pos = dev->pm_cap + PCI_PM_CTRL;
pci_read_config_word(dev, pmcsr_pos, &pmcsr);
+ if (pmcsr == (u16) PCI_ERROR_RESPONSE)
+ return false;
+
if (!(pmcsr & PCI_PM_CTRL_PME_STATUS))
return false;
--
2.22.0.770.g0f2c4a37fd-goog
next prev parent reply other threads:[~2019-08-05 20:52 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-05 20:52 [PATCH 0/5] PCI: Add PCI_ERROR_RESPONSE, check for errors Bjorn Helgaas
2019-08-05 20:52 ` [PATCH 1/5] PCI: Add PCI_ERROR_RESPONSE definition Bjorn Helgaas
2019-08-05 21:16 ` Rafael J. Wysocki
2019-08-05 20:52 ` [PATCH 2/5] PCI / PM: Return error when changing power state from D3cold Bjorn Helgaas
2019-08-05 21:15 ` Rafael J. Wysocki
2019-08-05 20:52 ` Bjorn Helgaas [this message]
2019-08-05 21:02 ` [PATCH 3/5] PCI / PM: Check for error when reading PME status Rafael J. Wysocki
2019-08-06 13:36 ` Bjorn Helgaas
2019-08-13 23:26 ` Rafael J. Wysocki
2019-08-14 1:15 ` Bjorn Helgaas
2019-08-05 20:52 ` [PATCH 4/5] PCI / PM: Check for error when reading Power State Bjorn Helgaas
2019-08-05 21:09 ` Rafael J. Wysocki
2019-08-09 22:01 ` Bjorn Helgaas
2019-08-13 22:59 ` Rafael J. Wysocki
2019-08-14 1:08 ` Bjorn Helgaas
2019-08-05 20:52 ` [PATCH 5/5] PCI / PM: Decode D3cold power state correctly Bjorn Helgaas
2019-08-05 21:14 ` Rafael J. Wysocki
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