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| author | Lukas Wunner <lukas@wunner.de> | 2023-01-15 09:20:31 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-03-10 09:29:53 +0100 |
| commit | 1ec8738fe38a094ce0e7a10f7bb318d9694ede7b (patch) | |
| tree | f4c91546874dd78cc75bc2e9588d95f1e3235b63 | |
| parent | 5475b05b5fe492d8f727f50ea6abed6fe9ca8885 (diff) | |
| download | linux-1ec8738fe38a094ce0e7a10f7bb318d9694ede7b.tar.gz linux-1ec8738fe38a094ce0e7a10f7bb318d9694ede7b.tar.bz2 linux-1ec8738fe38a094ce0e7a10f7bb318d9694ede7b.zip | |
PCI/PM: Observe reset delay irrespective of bridge_d3
commit 8ef0217227b42e2c34a18de316cee3da16c9bf1e upstream.
If a PCI bridge is suspended to D3cold upon entering system sleep,
resuming it entails a Fundamental Reset per PCIe r6.0 sec 5.8.
The delay prescribed after a Fundamental Reset in PCIe r6.0 sec 6.6.1
is sought to be observed by:
pci_pm_resume_noirq()
pci_pm_bridge_power_up_actions()
pci_bridge_wait_for_secondary_bus()
However, pci_bridge_wait_for_secondary_bus() bails out if the bridge_d3
flag is not set. That flag indicates whether a bridge is allowed to
suspend to D3cold at *runtime*.
Hence *no* delay is observed on resume from system sleep if runtime
D3cold is forbidden. That doesn't make any sense, so drop the bridge_d3
check from pci_bridge_wait_for_secondary_bus().
The purpose of the bridge_d3 check was probably to avoid delays if a
bridge remained in D0 during suspend. However the sole caller of
pci_bridge_wait_for_secondary_bus(), pci_pm_bridge_power_up_actions(),
is only invoked if the previous power state was D3cold. Hence the
additional bridge_d3 check seems superfluous.
Fixes: ad9001f2f411 ("PCI/PM: Add missing link delays required by the PCIe spec")
Link: https://lore.kernel.org/r/eb37fa345285ec8bacabbf06b020b803f77bdd3d.1673769517.git.lukas@wunner.de
Tested-by: Ravi Kishore Koppuravuri <ravi.kishore.koppuravuri@intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Cc: stable@vger.kernel.org # v5.5+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/pci/pci.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 5641786bd020..de99cdcd077e 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4957,7 +4957,7 @@ void pci_bridge_wait_for_secondary_bus(struct pci_dev *dev) if (pci_dev_is_disconnected(dev)) return; - if (!pci_is_bridge(dev) || !dev->bridge_d3) + if (!pci_is_bridge(dev)) return; down_read(&pci_bus_sem); |