| Message ID | 20160519113630.GT2043@lahna.fi.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On Thu, May 19, 2016 at 02:36:30PM +0300, Mika Westerberg wrote: > On Thu, May 19, 2016 at 10:42:31AM +0300, Mika Westerberg wrote: > > On Wed, May 18, 2016 at 07:14:01PM +0200, Peter Wu wrote: > > > Hi, > > > > > > While testing the pci/pm tree from Bjorn with HEAD being 0195d2813547 > > > ("PCI: Add runtime PM support for PCIe ports"), I have noticed that > > > detaching and rescanning is broken. > > > > > > When a bridgr is in D3 state, it cannot discover children. Reproducer: > > > > > > echo > /sys/bus/pci/devices/0000:01:00.0/remove 1 > > > # wait for the PCIe port to enter D3cold > > > echo > /sys/bus/pci/devices/0000:00:01.0/rescan 1 > > > # Workaround to get the device back > > > echo > /sys/bus/pci/devices/0000:00:01.0/power/control on > > > echo > /sys/bus/pci/devices/0000:00:01.0/rescan 1 > > > > > > lspci: > > > > > > 00:01.0 PCI bridge [0604]: Intel Corporation Skylake PCIe Controller (x16) [8086:1901] (rev 07) > > > 01:00.0 VGA compatible controller [0300]: NVIDIA Corporation GM204M [GeForce GTX 965M] [10de:13d9] (rev a1) > > > > > > Probably needs a pm_runtime_{get,put}_sync in pci_rescan_bus and > > > pci_rescan_bus_bridge_resize. > > > > Thanks for reporting. Let me investigate this a bit. > > I think it is enough if we make sure the bridge is powered when it is > being scanned. Can you try if the below patch works for you? > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 8004f67c57ec..15e77c92311e 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -16,6 +16,7 @@ > #include <linux/aer.h> > #include <linux/acpi.h> > #include <linux/irqdomain.h> > +#include <linux/pm_runtime.h> > #include "pci.h" > > #define CARDBUS_LATENCY_TIMER 176 /* secondary latency timer */ > @@ -832,6 +833,12 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass) > u8 primary, secondary, subordinate; > int broken = 0; > > + /* > + * Make sure the bridge is powered on to be able to access config > + * space of devices below it. > + */ > + pm_runtime_get_sync(&dev->dev); > + > pci_read_config_dword(dev, PCI_PRIMARY_BUS, &buses); > primary = buses & 0xFF; > secondary = (buses >> 8) & 0xFF; > @@ -1012,6 +1019,8 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass) > out: > pci_write_config_word(dev, PCI_BRIDGE_CONTROL, bctl); > > + pm_runtime_put(&dev->dev); > + > return max; > } > EXPORT_SYMBOL(pci_scan_bridge); Works for me on top of v4.6-rc7-216-g021351f. May 20 01:08:27.340318 localhost kernel: pci 0000:01:00.0: PME# disabled May 20 01:08:27.340589 localhost kernel: vgaarb: device changed decodes: PCI:0000:00:02.0,olddecodes=none,decodes=io+mem:owns=io+mem May 20 01:08:27.340755 localhost kernel: pcieport 0000:00:01.0: PME# enabled May 20 01:08:27.388476 localhost kernel: pcieport 0000:00:01.0: power state changed by ACPI to D3cold May 20 01:08:35.884288 localhost kernel: pci_bus 0000:00: scanning bus May 20 01:08:36.033274 localhost kernel: pcieport 0000:00:01.0: power state changed by ACPI to D0 May 20 01:08:36.135063 localhost kernel: pcieport 0000:00:01.0: PME# disabled May 20 01:08:36.136529 localhost kernel: pcieport 0000:00:01.0: scanning [bus 01-01] behind bridge, pass 0 May 20 01:08:36.136641 localhost kernel: pci_bus 0000:01: scanning bus May 20 01:08:36.138618 localhost kernel: pci 0000:01:00.0: [10de:13d9] type 00 class 0x030000 May 20 01:08:36.138661 localhost kernel: pci 0000:01:00.0: reg 0x10: [mem 0x00000000-0x00ffffff] May 20 01:08:36.138693 localhost kernel: pci 0000:01:00.0: reg 0x14: [mem 0x00000000-0x0fffffff 64bit pref] May 20 01:08:36.139226 localhost kernel: pci 0000:01:00.0: reg 0x1c: [mem 0x00000000-0x01ffffff 64bit pref] May 20 01:08:36.140360 localhost kernel: pci 0000:01:00.0: reg 0x24: [io 0x0000-0x007f] May 20 01:08:36.140384 localhost kernel: pci 0000:01:00.0: reg 0x30: [mem 0x00000000-0x0007ffff pref] May 20 01:08:36.141517 localhost kernel: pci 0000:01:00.0: Max Payload Size set to 256 (was 128, max 256) May 20 01:08:36.152493 localhost kernel: pci 0000:01:00.0: System wakeup disabled by ACPI May 20 01:08:36.153654 localhost kernel: vgaarb: device added: PCI:0000:01:00.0,decodes=io+mem,owns=none,locks=none May 20 01:08:36.153681 localhost kernel: vgaarb: device changed decodes: PCI:0000:00:02.0,olddecodes=io+mem,decodes=none:owns=io+mem May 20 01:08:36.157541 localhost kernel: pci_bus 0000:01: bus scan returning with max=01 May 20 01:08:36.157646 localhost kernel: pcieport 0000:00:1c.0: scanning [bus 02-02] behind bridge, pass 0 May 20 01:08:36.157730 localhost kernel: pci_bus 0000:02: scanning bus May 20 01:08:36.158865 localhost kernel: pci_bus 0000:02: bus scan returning with max=02 May 20 01:08:36.158964 localhost kernel: pcieport 0000:00:1c.5: scanning [bus 03-03] behind bridge, pass 0 May 20 01:08:36.159567 localhost kernel: pci_bus 0000:03: scanning bus May 20 01:08:36.160807 localhost kernel: pci_bus 0000:03: bus scan returning with max=03 May 20 01:08:36.160901 localhost kernel: pcieport 0000:00:01.0: scanning [bus 01-01] behind bridge, pass 1 May 20 01:08:36.161527 localhost kernel: pcieport 0000:00:1c.0: scanning [bus 02-02] behind bridge, pass 1 May 20 01:08:36.162753 localhost kernel: pcieport 0000:00:1c.5: scanning [bus 03-03] behind bridge, pass 1 May 20 01:08:36.162832 localhost kernel: pci_bus 0000:00: bus scan returning with max=03 May 20 01:08:36.164654 localhost kernel: pci 0000:01:00.0: BAR 1: assigned [mem 0xc0000000-0xcfffffff 64bit pref] May 20 01:08:36.164762 localhost kernel: pci 0000:01:00.0: BAR 3: assigned [mem 0xd0000000-0xd1ffffff 64bit pref] May 20 01:08:36.164847 localhost kernel: pci 0000:01:00.0: BAR 0: assigned [mem 0xde000000-0xdeffffff] May 20 01:08:36.165284 localhost kernel: pci 0000:01:00.0: BAR 6: assigned [mem 0xdf000000-0xdf07ffff pref] May 20 01:08:36.166515 localhost kernel: pci 0000:01:00.0: BAR 5: assigned [io 0xe000-0xe07f] May 20 01:08:36.166612 localhost kernel: pci 0000:01:00.0: calling nv_msi_ht_cap_quirk_leaf+0x0/0x20 May 20 01:08:36.167799 localhost kernel: pci 0000:01:00.0: calling pci_fixup_video+0x0/0x100
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 8004f67c57ec..15e77c92311e 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -16,6 +16,7 @@ #include <linux/aer.h> #include <linux/acpi.h> #include <linux/irqdomain.h> +#include <linux/pm_runtime.h> #include "pci.h" #define CARDBUS_LATENCY_TIMER 176 /* secondary latency timer */ @@ -832,6 +833,12 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass) u8 primary, secondary, subordinate; int broken = 0; + /* + * Make sure the bridge is powered on to be able to access config + * space of devices below it. + */ + pm_runtime_get_sync(&dev->dev); + pci_read_config_dword(dev, PCI_PRIMARY_BUS, &buses); primary = buses & 0xFF; secondary = (buses >> 8) & 0xFF; @@ -1012,6 +1019,8 @@ int pci_scan_bridge(struct pci_bus *bus, struct pci_dev *dev, int max, int pass) out: pci_write_config_word(dev, PCI_BRIDGE_CONTROL, bctl); + pm_runtime_put(&dev->dev); + return max; } EXPORT_SYMBOL(pci_scan_bridge);