From: Michael Bottini <[email protected]>
Devices that appear under the Intel VMD host bridge are not visible to BIOS
and therefore not programmed by BIOS with ASPM settings. For these devices,
it is necessary for the driver to configure ASPM. Since ASPM settings are
adjustable at runtime by module parameter, use the same mechanism to allow
drivers to override the default (in this case never configured) BIOS policy
to ASPM_STATE_ALL. Then, reconfigure ASPM on the link. Do not override if
ASPM control is disabled.
Signed-off-by: Michael Bottini <[email protected]>
Signed-off-by: David E. Box <[email protected]>
---
V2
- Change return type to int so caller can determine if override was
successful
- Return immediately if link is not found so that lock it not
unecessarily taken, suggested by [email protected]
- Don't override if aspm_disabled is true
drivers/pci/pci.h | 2 ++
drivers/pci/pcie/aspm.c | 19 +++++++++++++++++++
2 files changed, 21 insertions(+)
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 3d60cabde1a1..c741791f15e0 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -562,11 +562,13 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev);
void pcie_aspm_exit_link_state(struct pci_dev *pdev);
void pcie_aspm_pm_state_change(struct pci_dev *pdev);
void pcie_aspm_powersave_config_link(struct pci_dev *pdev);
+int pcie_aspm_policy_override(struct pci_dev *dev);
#else
static inline void pcie_aspm_init_link_state(struct pci_dev *pdev) { }
static inline void pcie_aspm_exit_link_state(struct pci_dev *pdev) { }
static inline void pcie_aspm_pm_state_change(struct pci_dev *pdev) { }
static inline void pcie_aspm_powersave_config_link(struct pci_dev *pdev) { }
+static inline int pcie_aspm_policy_override(struct pci_dev *dev) { return -EINVAL }
#endif
#ifdef CONFIG_PCIE_ECRC
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 52c74682601a..e2c61e14e724 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -1140,6 +1140,25 @@ int pci_disable_link_state(struct pci_dev *pdev, int state)
}
EXPORT_SYMBOL(pci_disable_link_state);
+int pcie_aspm_policy_override(struct pci_dev *pdev)
+{
+ struct pcie_link_state *link = pcie_aspm_get_link(pdev);
+
+ if (!link || aspm_disabled)
+ return -EINVAL;
+
+ down_read(&pci_bus_sem);
+ mutex_lock(&aspm_lock);
+ link->aspm_default = ASPM_STATE_ALL;
+ pcie_config_aspm_link(link, policy_to_aspm_state(link));
+ pcie_set_clkpm(link, policy_to_clkpm_state(link));
+ mutex_unlock(&aspm_lock);
+ up_read(&pci_bus_sem);
+
+ return 0;
+}
+EXPORT_SYMBOL(pcie_aspm_policy_override);
+
static int pcie_aspm_set_policy(const char *val,
const struct kernel_param *kp)
{
--
2.25.1
From: Michael Bottini <[email protected]>
On Tiger Lake and Alder Lake platforms, VMD controllers do not have ASPM
enabled nor LTR values set by BIOS. This leads high power consumption on
these platforms when VMD is enabled as reported in bugzilla [1]. Enable
these features in the VMD driver using pcie_aspm_policy_override() to set
the ASPM policy for the root ports.
To do this, add an additional flag in VMD features to specify devices that
must have their respective policies overridden.
[1] https://bugzilla.kernel.org/show_bug.cgi?id=213717
Signed-off-by: Michael Bottini <[email protected]>
Signed-off-by: David E. Box <[email protected]>
Tested-by: Adhitya Mohan <[email protected]>
---
V2
- Use return status to print pci_info message if ASPM cannot be enabled.
- Add missing static declaration, caught by [email protected]
drivers/pci/controller/vmd.c | 42 +++++++++++++++++++++++++++++++++---
1 file changed, 39 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
index a45e8e59d3d4..e555dcae73cc 100644
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -20,6 +20,8 @@
#include <asm/irqdomain.h>
+#include "../pci.h"
+
#define VMD_CFGBAR 0
#define VMD_MEMBAR1 2
#define VMD_MEMBAR2 4
@@ -67,6 +69,12 @@ enum vmd_features {
* interrupt handling.
*/
VMD_FEAT_CAN_BYPASS_MSI_REMAP = (1 << 4),
+
+ /*
+ * Device must have ASPM policy overridden, as its default policy is
+ * incorrect.
+ */
+ VMD_FEAT_QUIRK_OVERRIDE_ASPM = (1 << 5),
};
static DEFINE_IDA(vmd_instance_ida);
@@ -661,6 +669,29 @@ static int vmd_alloc_irqs(struct vmd_dev *vmd)
return 0;
}
+/*
+ * Override the BIOS ASPM policy and set the LTR value for PCI storage
+ * devices on the VMD bride.
+ */
+static int vmd_enable_aspm(struct pci_dev *pdev, void *userdata)
+{
+ int features = *(int *)userdata;
+
+ if (features & VMD_FEAT_QUIRK_OVERRIDE_ASPM &&
+ pdev->class == PCI_CLASS_STORAGE_EXPRESS) {
+ int pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_LTR);
+
+ if (pos) {
+ pci_write_config_word(pdev, pos + PCI_LTR_MAX_SNOOP_LAT, 0x1003);
+ pci_write_config_word(pdev, pos + PCI_LTR_MAX_NOSNOOP_LAT, 0x1003);
+ if (pcie_aspm_policy_override(pdev))
+ pci_info(pdev, "Unable of override ASPM policy\n");
+ }
+ }
+
+ return 0;
+}
+
static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
{
struct pci_sysdata *sd = &vmd->sysdata;
@@ -807,6 +838,8 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
pci_scan_child_bus(vmd->bus);
pci_assign_unassigned_bus_resources(vmd->bus);
+ pci_walk_bus(vmd->bus, vmd_enable_aspm, &features);
+
/*
* VMD root buses are virtual and don't return true on pci_is_pcie()
* and will fail pcie_bus_configure_settings() early. It can instead be
@@ -948,15 +981,18 @@ static const struct pci_device_id vmd_ids[] = {
{PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x467f),
.driver_data = VMD_FEAT_HAS_MEMBAR_SHADOW_VSCAP |
VMD_FEAT_HAS_BUS_RESTRICTIONS |
- VMD_FEAT_OFFSET_FIRST_VECTOR,},
+ VMD_FEAT_OFFSET_FIRST_VECTOR |
+ VMD_FEAT_QUIRK_OVERRIDE_ASPM,},
{PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x4c3d),
.driver_data = VMD_FEAT_HAS_MEMBAR_SHADOW_VSCAP |
VMD_FEAT_HAS_BUS_RESTRICTIONS |
- VMD_FEAT_OFFSET_FIRST_VECTOR,},
+ VMD_FEAT_OFFSET_FIRST_VECTOR |
+ VMD_FEAT_QUIRK_OVERRIDE_ASPM,},
{PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_VMD_9A0B),
.driver_data = VMD_FEAT_HAS_MEMBAR_SHADOW_VSCAP |
VMD_FEAT_HAS_BUS_RESTRICTIONS |
- VMD_FEAT_OFFSET_FIRST_VECTOR,},
+ VMD_FEAT_OFFSET_FIRST_VECTOR |
+ VMD_FEAT_QUIRK_OVERRIDE_ASPM,},
{0,}
};
MODULE_DEVICE_TABLE(pci, vmd_ids);
--
2.25.1
Hi "David,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on v5.16-rc4]
[also build test ERROR on next-20211207]
[cannot apply to helgaas-pci/next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/David-E-Box/PCI-ASPM-Add-ASPM-BIOS-override-function/20211208-063240
base: 0fcfb00b28c0b7884635dacf38e46d60bf3d4eb1
config: nds32-defconfig (https://download.01.org/0day-ci/archive/20211208/[email protected]/config)
compiler: nds32le-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/efd5524bd4005ec84d4eb6681c54d1ba93fe9ca1
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review David-E-Box/PCI-ASPM-Add-ASPM-BIOS-override-function/20211208-063240
git checkout efd5524bd4005ec84d4eb6681c54d1ba93fe9ca1
# save the config file to linux build tree
mkdir build_dir
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=nds32 SHELL=/bin/bash
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <[email protected]>
All errors (new ones prefixed by >>):
In file included from drivers/pci/of.c:16:
drivers/pci/pci.h: In function 'pcie_aspm_policy_override':
>> drivers/pci/pci.h:571:83: error: expected ';' before '}' token
571 | static inline int pcie_aspm_policy_override(struct pci_dev *dev) { return -EINVAL }
| ^
vim +571 drivers/pci/pci.h
553
554 /* PCI error reporting and recovery */
555 pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
556 pci_channel_state_t state,
557 pci_ers_result_t (*reset_subordinates)(struct pci_dev *pdev));
558
559 bool pcie_wait_for_link(struct pci_dev *pdev, bool active);
560 #ifdef CONFIG_PCIEASPM
561 void pcie_aspm_init_link_state(struct pci_dev *pdev);
562 void pcie_aspm_exit_link_state(struct pci_dev *pdev);
563 void pcie_aspm_pm_state_change(struct pci_dev *pdev);
564 void pcie_aspm_powersave_config_link(struct pci_dev *pdev);
565 int pcie_aspm_policy_override(struct pci_dev *dev);
566 #else
567 static inline void pcie_aspm_init_link_state(struct pci_dev *pdev) { }
568 static inline void pcie_aspm_exit_link_state(struct pci_dev *pdev) { }
569 static inline void pcie_aspm_pm_state_change(struct pci_dev *pdev) { }
570 static inline void pcie_aspm_powersave_config_link(struct pci_dev *pdev) { }
> 571 static inline int pcie_aspm_policy_override(struct pci_dev *dev) { return -EINVAL }
572 #endif
573
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/[email protected]