| Message ID | 20200514070554.17069-2-koba.ko@canonical.com |
|---|---|
| State | New |
| Headers | show |
| Series | UBUNTU: SAUCE: pci: Speed up the process of s3 resume | expand |
> On May 14, 2020, at 15:05, koba.ko@canonical.com wrote: > > From: Mika Westerberg <mika.westerberg@linux.intel.com> Mika proposed a v2 here: https://lore.kernel.org/linux-pci/20200514133043.27429-1-mika.westerberg@linux.intel.com/ I haven't tested it though. Kai-Heng > > BugLink: https://bugs.launchpad.net/bugs/1876844 If this is not that urgent, we can wait till it lands to PCI maintainer's tree. Kai-Heng > > Kai-Heng Feng reported that it takes long time (>1s) to resume > Thunderbolt connected PCIe devices from both runtime suspend and system > sleep (s2idle). > > These PCIe downstream ports the second link capability (PCI_EXP_LNKCAP2) > announces support for speeds > 5 GT/s but it is then capped by the > second link control (PCI_EXP_LNKCTL2) register to 2.5 GT/s. This > possiblity was not considered in pci_bridge_wait_for_secondary_bus() so > it ended up waiting for 1100 ms as these ports do not support active > link layer reporting either. > > PCIe spec 5.0 section 6.6.1 mandates that we must wait minimum of 100 ms > before sending configuration request to the device below, if the port > does not support speeds > 5 GT/s, and if it does we first need to wait > for the data link layer to become active before waiting for that 100 ms. > > PCIe spec 5.0 section 7.5.3.6 further says that all downstream ports > that support speeds > 5 GT/s must support active link layer reporting so > instead of looking for the speed we can check for the active link layer > reporting capability and determine how to wait based on that (as they go > hand in hand). > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=206837 > Reported-by: Kai-Heng Feng <kai.heng.feng@canonical.com> > Tested-by: Kai-Heng Feng <kai.heng.feng@canonical.com> > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> > (cherry picked from > https://lore.kernel.org/linux-pci/20200416083245.73957-1-mika.westerberg@linux.intel.com/) > Signed-off-by: Koba Ko <koba.ko@canonical.com> > --- > drivers/pci/pci.c | 8 +++++++- > 1 file changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index d828ca835a98..ebe626ad1b79 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -4765,7 +4765,13 @@ void pci_bridge_wait_for_secondary_bus(struct pci_dev *dev) > if (!pcie_downstream_port(dev)) > return; > > - if (pcie_get_speed_cap(dev) <= PCIE_SPEED_5_0GT) { > + /* > + * Since PCIe spec mandates that all downstream ports that support > + * speeds greater than 5 GT/s must support data link layer active > + * reporting so we use that here to determine when the delay should > + * be issued. > + */ > + if (!dev->link_active_reporting) { > pci_dbg(dev, "waiting %d ms for downstream link\n", delay); > msleep(delay); > } else { > -- > 2.17.1 > > > -- > kernel-team mailing list > kernel-team@lists.ubuntu.com > https://lists.ubuntu.com/mailman/listinfo/kernel-team
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index d828ca835a98..ebe626ad1b79 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4765,7 +4765,13 @@ void pci_bridge_wait_for_secondary_bus(struct pci_dev *dev) if (!pcie_downstream_port(dev)) return; - if (pcie_get_speed_cap(dev) <= PCIE_SPEED_5_0GT) { + /* + * Since PCIe spec mandates that all downstream ports that support + * speeds greater than 5 GT/s must support data link layer active + * reporting so we use that here to determine when the delay should + * be issued. + */ + if (!dev->link_active_reporting) { pci_dbg(dev, "waiting %d ms for downstream link\n", delay); msleep(delay); } else {