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Rozycki" , linux-kernel@vger.kernel.org Cc: Mika Westerberg , =?utf-8?q?Ilpo_J?= =?utf-8?q?=C3=A4rvinen?= Subject: [PATCH 2/2] PCI: Do not wait for disconnected devices when resuming Date: Mon, 29 Jan 2024 13:27:10 +0200 Message-Id: <20240129112710.2852-3-ilpo.jarvinen@linux.intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240129112710.2852-1-ilpo.jarvinen@linux.intel.com> References: <20240129112710.2852-1-ilpo.jarvinen@linux.intel.com> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On runtime resume, pci_dev_wait() is called: pci_pm_runtime_resume() pci_pm_bridge_power_up_actions() pci_bridge_wait_for_secondary_bus() pci_dev_wait() While a device is runtime suspended along with its PCIe hierarchy, the device could get disconnected. In such case, the link will not come up no matter how log pci_dev_wait() waits for it. Besides the above mentioned case, there could be other ways to get the device disconnected while pci_dev_wait() is waiting for the link to come up. Make pci_dev_wait() to exit if the device is already disconnected to avoid unnecessary delay. As disconnected device is not really even a failure in the same sense as link failing to come up for whatever reason, return 0 instead of errno. Also make sure compiler does not become too clever with dev->error_state and use READ_ONCE() to force a fetch for the up-to-date value. Reported-by: Mika Westerberg Tested-by: Mika Westerberg Signed-off-by: Ilpo Järvinen --- drivers/pci/pci.c | 5 +++++ drivers/pci/pci.h | 4 +++- 2 files changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index d8f11a078924..ec9bf6c90312 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -1250,6 +1250,11 @@ static int pci_dev_wait(struct pci_dev *dev, char *reset_type, int timeout) for (;;) { u32 id; + if (pci_dev_is_disconnected(dev)) { + pci_dbg(dev, "disconnected; not waiting\n"); + return 0; + } + pci_read_config_dword(dev, PCI_COMMAND, &id); if (!PCI_POSSIBLE_ERROR(id)) break; diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index 2336a8d1edab..563a275dff67 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -4,6 +4,8 @@ #include +#include + /* Number of possible devfns: 0.0 to 1f.7 inclusive */ #define MAX_NR_DEVFNS 256 @@ -370,7 +372,7 @@ static inline int pci_dev_set_disconnected(struct pci_dev *dev, void *unused) static inline bool pci_dev_is_disconnected(const struct pci_dev *dev) { - return dev->error_state == pci_channel_io_perm_failure; + return READ_ONCE(dev->error_state) == pci_channel_io_perm_failure; } /* pci_dev priv_flags */