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Revert "PCI/PM: Assume ports without DLL Link Active train links in 100 ms"

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This reverts commit ec411e02b7.

Patrick reported that this commit broke hybrid graphics on a ThinkPad X1
Extreme 2nd with Intel UHD Graphics 630 and NVIDIA GeForce GTX 1650 Mobile:

  nouveau 0000:01:00.0: fifo: PBDMA0: 01000000 [] ch 0 [00ff992000 DRM] subc 0 mthd 0008 data 00000000

Karol reported that this commit broke Nouveau firmware loading on a Lenovo
P1G2 with Intel UHD Graphics 630 and NVIDIA TU117GLM [Quadro T1000 Mobile]:

  nouveau 0000:01:00.0: acr: AHESASC binary failed

In both cases, reverting ec411e02b7 solved the problem.  Unfortunately,
this revert will reintroduce the "Thunderbolt bridges take long time to
resume from D3cold" problem:
https://bugzilla.kernel.org/show_bug.cgi?id=206837

Link: https://lore.kernel.org/r/CAErSpo5sTeK_my1dEhWp7aHD0xOp87+oHYWkTjbL7ALgDbXo-Q@mail.gmail.com
Link: https://lore.kernel.org/r/CACO55tsAEa5GXw5oeJPG=mcn+qxNvspXreJYWDJGZBy5v82JDA@mail.gmail.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=208597
Reported-by: Patrick Volkerding <volkerdi@gmail.com>
Reported-by: Karol Herbst <kherbst@redhat.com>
Fixes: ec411e02b7 ("PCI/PM: Assume ports without DLL Link Active train links in 100 ms")
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Bjorn Helgaas 2020-07-17 17:21:28 -05:00
parent 62ca18a089
commit d08c30d7a0
1 changed files with 9 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
drivers/pci/pci.c
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@ -4638,8 +4638,7 @@ static int pci_pm_reset(struct pci_dev *dev, int probe)
* pcie_wait_for_link_delay - Wait until link is active or inactive
* @pdev: Bridge device
* @active: waiting for active or inactive?
* @delay: Delay to wait after link has become active (in ms). Specify %0
* for no delay.
* @delay: Delay to wait after link has become active (in ms)
*
* Use this to wait till link becomes active or inactive.
*/
@ -4680,7 +4679,7 @@ static bool pcie_wait_for_link_delay(struct pci_dev *pdev, bool active,
msleep(10);
timeout -= 10;
}
if (active && ret && delay)
if (active && ret)
msleep(delay);
else if (ret != active)
pci_info(pdev, "Data Link Layer Link Active not %s in 1000 msec\n",
@ -4801,28 +4800,17 @@ void pci_bridge_wait_for_secondary_bus(struct pci_dev *dev)
if (!pcie_downstream_port(dev))
return;
/*
* Per PCIe r5.0, sec 6.6.1, for downstream ports that support
* speeds > 5 GT/s, we must wait for link training to complete
* before the mandatory delay.
*
* We can only tell when link training completes via DLL Link
* Active, which is required for downstream ports that support
* speeds > 5 GT/s (sec 7.5.3.6). Unfortunately some common
* devices do not implement Link Active reporting even when it's
* required, so we'll check for that directly instead of checking
* the supported link speed. We assume devices without Link Active
* reporting can train in 100 ms regardless of speed.
*/
if (dev->link_active_reporting) {
pci_dbg(dev, "waiting for link to train\n");
if (!pcie_wait_for_link_delay(dev, true, 0)) {
if (pcie_get_speed_cap(dev) <= PCIE_SPEED_5_0GT) {
pci_dbg(dev, "waiting %d ms for downstream link\n", delay);
msleep(delay);
} else {
pci_dbg(dev, "waiting %d ms for downstream link, after activation\n",
delay);
if (!pcie_wait_for_link_delay(dev, true, delay)) {
/* Did not train, no need to wait any further */
return;
}
}
pci_dbg(child, "waiting %d ms to become accessible\n", delay);
msleep(delay);
if (!pci_device_is_present(child)) {
pci_dbg(child, "waiting additional %d ms to become accessible\n", delay);