Re: [PATCH v6 1/4] ACPI/PCI: Ignore _OSC negotiation result if pcie_ports_native is set.
From: Kuppuswamy, Sathyanarayanan
Date: Sat Jul 11 2020 - 17:45:24 EST
Hi Bjorn,
On 7/9/20 4:07 PM, Bjorn Helgaas wrote:
On Fri, Jun 26, 2020 at 11:32:33AM -0700, sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx wrote:
From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
pcie_ports_native is set only if user requests native handling
of PCIe capabilities via pcie_port_setup command line option.
User input takes precedence over _OSC based control negotiation
result. So consider the _OSC negotiated result only if
pcie_ports_native is unset.
Also, since struct pci_host_bridge ->native_* members caches the
ownership status of various PCIe capabilities, use them instead
of distributed checks for pcie_ports_native.
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
---
drivers/acpi/pci_root.c | 26 ++++++++++++++------------
drivers/pci/hotplug/pciehp_core.c | 2 +-
drivers/pci/pci-acpi.c | 3 ---
drivers/pci/pcie/aer.c | 2 +-
drivers/pci/pcie/portdrv_core.c | 9 +++------
drivers/pci/probe.c | 5 +++--
6 files changed, 22 insertions(+), 25 deletions(-)
diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index f90e841c59f5..02fab8b0118e 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -914,18 +914,20 @@ struct pci_bus *acpi_pci_root_create(struct acpi_pci_root *root,
goto out_release_info;
host_bridge = to_pci_host_bridge(bus->bridge);
- if (!(root->osc_control_set & OSC_PCI_EXPRESS_NATIVE_HP_CONTROL))
- host_bridge->native_pcie_hotplug = 0;
- if (!(root->osc_control_set & OSC_PCI_SHPC_NATIVE_HP_CONTROL))
- host_bridge->native_shpc_hotplug = 0;
- if (!(root->osc_control_set & OSC_PCI_EXPRESS_AER_CONTROL))
- host_bridge->native_aer = 0;
- if (!(root->osc_control_set & OSC_PCI_EXPRESS_PME_CONTROL))
- host_bridge->native_pme = 0;
- if (!(root->osc_control_set & OSC_PCI_EXPRESS_LTR_CONTROL))
- host_bridge->native_ltr = 0;
- if (!(root->osc_control_set & OSC_PCI_EXPRESS_DPC_CONTROL))
- host_bridge->native_dpc = 0;
+ if (!pcie_ports_native) {
+ if (!(root->osc_control_set & OSC_PCI_EXPRESS_NATIVE_HP_CONTROL))
+ host_bridge->native_pcie_hotplug = 0;
+ if (!(root->osc_control_set & OSC_PCI_SHPC_NATIVE_HP_CONTROL))
+ host_bridge->native_shpc_hotplug = 0;
+ if (!(root->osc_control_set & OSC_PCI_EXPRESS_AER_CONTROL))
+ host_bridge->native_aer = 0;
+ if (!(root->osc_control_set & OSC_PCI_EXPRESS_PME_CONTROL))
+ host_bridge->native_pme = 0;
+ if (!(root->osc_control_set & OSC_PCI_EXPRESS_LTR_CONTROL))
+ host_bridge->native_ltr = 0;
+ if (!(root->osc_control_set & OSC_PCI_EXPRESS_DPC_CONTROL))
+ host_bridge->native_dpc = 0;
+ }
When the user boots with "pcie_ports=native", should we evaluate _OSC
at all?
Since pcie_ports="native" does not override
OSC_PCI_SHPC_NATIVE_HP_CONTROL, I think we should still evaluate _OSC.
Also firmware might still wants to know about supported features during
_OSC call.
It seems confusing to say "OK, Mr. Firmware, here are the
features we want to use", and then turn around and use them all
regardless of what the platform said. Why not just ignore the
firmware completely and go ahead and use everything?|
AFAIK, for PCIe features, It should functionally make no difference
(evaluating _OSC vs not). But, IMO, its useful if we print some warnings
if firmware denies some of the PCIe feature control.
I can't remember if there's a reason we need to call
negotiate_os_control() so early and then hang on to the results until
we get here:
acpi_pci_root_add
negotiate_os_control <--- eval _OSC
pci_acpi_scan_root
acpi_pci_root_create
pci_create_root_bus
if (!(root->osc_control_set & ...)) <--- use results
host_bridge->native_... = 0;
I think it would be a lot simpler if we could do the _OSC negotiation
right here where we need most of the results. It would be even better
if we could update the host_bridge->native_... items directly inside
negotiate_os_control() so we wouldn't have to hang onto the
osc_control_set mask.
Makes sense. I also don't see any one use _OSC negotiated results until
pci_create_root_bus(). But I think this should be a seperate patch.
/*
* Evaluate the "PCI Boot Configuration" _DSM Function. If it
diff --git a/drivers/pci/hotplug/pciehp_core.c b/drivers/pci/hotplug/pciehp_core.c
index bf779f291f15..5fc999bf6f1b 100644
--- a/drivers/pci/hotplug/pciehp_core.c
+++ b/drivers/pci/hotplug/pciehp_core.c
@@ -255,7 +255,7 @@ static bool pme_is_native(struct pcie_device *dev)
const struct pci_host_bridge *host;
host = pci_find_host_bridge(dev->port->bus);
- return pcie_ports_native || host->native_pme;
+ return host->native_pme;
}
static void pciehp_disable_interrupt(struct pcie_device *dev)
diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
index 7224b1e5f2a8..e09589571a9d 100644
--- a/drivers/pci/pci-acpi.c
+++ b/drivers/pci/pci-acpi.c
@@ -800,9 +800,6 @@ bool pciehp_is_native(struct pci_dev *bridge)
if (!(slot_cap & PCI_EXP_SLTCAP_HPC))
return false;
- if (pcie_ports_native)
- return true;
-
host = pci_find_host_bridge(bridge->bus);
return host->native_pcie_hotplug;
}
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 3acf56683915..d663bd9c7257 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -219,7 +219,7 @@ int pcie_aer_is_native(struct pci_dev *dev)
if (!dev->aer_cap)
return 0;
- return pcie_ports_native || host->native_aer;
+ return host->native_aer;
}
int pci_enable_pcie_error_reporting(struct pci_dev *dev)
diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
index 50a9522ab07d..ccd5e0ce5605 100644
--- a/drivers/pci/pcie/portdrv_core.c
+++ b/drivers/pci/pcie/portdrv_core.c
@@ -208,8 +208,7 @@ static int get_port_device_capability(struct pci_dev *dev)
struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
int services = 0;
- if (dev->is_hotplug_bridge &&
- (pcie_ports_native || host->native_pcie_hotplug)) {
+ if (dev->is_hotplug_bridge && host->native_pcie_hotplug) {
services |= PCIE_PORT_SERVICE_HP;
/*
@@ -221,8 +220,7 @@ static int get_port_device_capability(struct pci_dev *dev)
}
#ifdef CONFIG_PCIEAER
- if (dev->aer_cap && pci_aer_available() &&
- (pcie_ports_native || host->native_aer)) {
+ if (dev->aer_cap && pci_aer_available() && host->native_aer) {
services |= PCIE_PORT_SERVICE_AER;
/*
@@ -238,8 +236,7 @@ static int get_port_device_capability(struct pci_dev *dev)
* Event Collectors can also generate PMEs, but we don't handle
* those yet.
*/
- if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT &&
- (pcie_ports_native || host->native_pme)) {
+ if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT && host->native_pme) {
services |= PCIE_PORT_SERVICE_PME;
I *love* that you removed pcie_ports_native from all these places.
/*
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 2f66988cea25..5fb90bb9b4e3 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -588,13 +588,14 @@ static void pci_init_host_bridge(struct pci_host_bridge *bridge)
* may implement its own AER handling and use _OSC to prevent the
* OS from interfering.
*/
+#ifdef CONFIG_PCIEPORTBUS
bridge->native_aer = 1;
bridge->native_pcie_hotplug = 1;
- bridge->native_shpc_hotplug = 1;
bridge->native_pme = 1;
bridge->native_ltr = 1;
bridge->native_dpc = 1;
-
+#endif
+ bridge->native_shpc_hotplug = 1;
This looks like a bugfix that should be its own patch.
Agreed. I will split it in next version.
device_initialize(&bridge->dev);
}
--
2.17.1
--
Sathyanarayanan Kuppuswamy
Linux Kernel Developer