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path: root/drivers/pci/pcie/aspm.c
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Diffstat (limited to 'drivers/pci/pcie/aspm.c')
-rw-r--r--drivers/pci/pcie/aspm.c282
1 files changed, 177 insertions, 105 deletions
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 71222814c1e..e1e7026b838 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -69,13 +69,22 @@ struct pcie_link_state {
};
static int aspm_disabled, aspm_force;
+static bool aspm_support_enabled = true;
static DEFINE_MUTEX(aspm_lock);
static LIST_HEAD(link_list);
#define POLICY_DEFAULT 0 /* BIOS default setting */
#define POLICY_PERFORMANCE 1 /* high performance */
#define POLICY_POWERSAVE 2 /* high power saving */
+
+#ifdef CONFIG_PCIEASPM_PERFORMANCE
+static int aspm_policy = POLICY_PERFORMANCE;
+#elif defined CONFIG_PCIEASPM_POWERSAVE
+static int aspm_policy = POLICY_POWERSAVE;
+#else
static int aspm_policy;
+#endif
+
static const char *policy_str[] = {
[POLICY_DEFAULT] = "default",
[POLICY_PERFORMANCE] = "performance",
@@ -116,21 +125,16 @@ static int policy_to_clkpm_state(struct pcie_link_state *link)
static void pcie_set_clkpm_nocheck(struct pcie_link_state *link, int enable)
{
- int pos;
- u16 reg16;
struct pci_dev *child;
struct pci_bus *linkbus = link->pdev->subordinate;
list_for_each_entry(child, &linkbus->devices, bus_list) {
- pos = pci_pcie_cap(child);
- if (!pos)
- return;
- pci_read_config_word(child, pos + PCI_EXP_LNKCTL, &reg16);
if (enable)
- reg16 |= PCI_EXP_LNKCTL_CLKREQ_EN;
+ pcie_capability_set_word(child, PCI_EXP_LNKCTL,
+ PCI_EXP_LNKCTL_CLKREQ_EN);
else
- reg16 &= ~PCI_EXP_LNKCTL_CLKREQ_EN;
- pci_write_config_word(child, pos + PCI_EXP_LNKCTL, reg16);
+ pcie_capability_clear_word(child, PCI_EXP_LNKCTL,
+ PCI_EXP_LNKCTL_CLKREQ_EN);
}
link->clkpm_enabled = !!enable;
}
@@ -139,7 +143,7 @@ static void pcie_set_clkpm(struct pcie_link_state *link, int enable)
{
/* Don't enable Clock PM if the link is not Clock PM capable */
if (!link->clkpm_capable && enable)
- return;
+ enable = 0;
/* Need nothing if the specified equals to current state */
if (link->clkpm_enabled == enable)
return;
@@ -148,7 +152,7 @@ static void pcie_set_clkpm(struct pcie_link_state *link, int enable)
static void pcie_clkpm_cap_init(struct pcie_link_state *link, int blacklist)
{
- int pos, capable = 1, enabled = 1;
+ int capable = 1, enabled = 1;
u32 reg32;
u16 reg16;
struct pci_dev *child;
@@ -156,16 +160,13 @@ static void pcie_clkpm_cap_init(struct pcie_link_state *link, int blacklist)
/* All functions should have the same cap and state, take the worst */
list_for_each_entry(child, &linkbus->devices, bus_list) {
- pos = pci_pcie_cap(child);
- if (!pos)
- return;
- pci_read_config_dword(child, pos + PCI_EXP_LNKCAP, &reg32);
+ pcie_capability_read_dword(child, PCI_EXP_LNKCAP, &reg32);
if (!(reg32 & PCI_EXP_LNKCAP_CLKPM)) {
capable = 0;
enabled = 0;
break;
}
- pci_read_config_word(child, pos + PCI_EXP_LNKCTL, &reg16);
+ pcie_capability_read_word(child, PCI_EXP_LNKCTL, &reg16);
if (!(reg16 & PCI_EXP_LNKCTL_CLKREQ_EN))
enabled = 0;
}
@@ -181,7 +182,7 @@ static void pcie_clkpm_cap_init(struct pcie_link_state *link, int blacklist)
*/
static void pcie_aspm_configure_common_clock(struct pcie_link_state *link)
{
- int ppos, cpos, same_clock = 1;
+ int same_clock = 1;
u16 reg16, parent_reg, child_reg[8];
unsigned long start_jiffies;
struct pci_dev *child, *parent = link->pdev;
@@ -194,46 +195,43 @@ static void pcie_aspm_configure_common_clock(struct pcie_link_state *link)
BUG_ON(!pci_is_pcie(child));
/* Check downstream component if bit Slot Clock Configuration is 1 */
- cpos = pci_pcie_cap(child);
- pci_read_config_word(child, cpos + PCI_EXP_LNKSTA, &reg16);
+ pcie_capability_read_word(child, PCI_EXP_LNKSTA, &reg16);
if (!(reg16 & PCI_EXP_LNKSTA_SLC))
same_clock = 0;
/* Check upstream component if bit Slot Clock Configuration is 1 */
- ppos = pci_pcie_cap(parent);
- pci_read_config_word(parent, ppos + PCI_EXP_LNKSTA, &reg16);
+ pcie_capability_read_word(parent, PCI_EXP_LNKSTA, &reg16);
if (!(reg16 & PCI_EXP_LNKSTA_SLC))
same_clock = 0;
/* Configure downstream component, all functions */
list_for_each_entry(child, &linkbus->devices, bus_list) {
- cpos = pci_pcie_cap(child);
- pci_read_config_word(child, cpos + PCI_EXP_LNKCTL, &reg16);
+ pcie_capability_read_word(child, PCI_EXP_LNKCTL, &reg16);
child_reg[PCI_FUNC(child->devfn)] = reg16;
if (same_clock)
reg16 |= PCI_EXP_LNKCTL_CCC;
else
reg16 &= ~PCI_EXP_LNKCTL_CCC;
- pci_write_config_word(child, cpos + PCI_EXP_LNKCTL, reg16);
+ pcie_capability_write_word(child, PCI_EXP_LNKCTL, reg16);
}
/* Configure upstream component */
- pci_read_config_word(parent, ppos + PCI_EXP_LNKCTL, &reg16);
+ pcie_capability_read_word(parent, PCI_EXP_LNKCTL, &reg16);
parent_reg = reg16;
if (same_clock)
reg16 |= PCI_EXP_LNKCTL_CCC;
else
reg16 &= ~PCI_EXP_LNKCTL_CCC;
- pci_write_config_word(parent, ppos + PCI_EXP_LNKCTL, reg16);
+ pcie_capability_write_word(parent, PCI_EXP_LNKCTL, reg16);
/* Retrain link */
reg16 |= PCI_EXP_LNKCTL_RL;
- pci_write_config_word(parent, ppos + PCI_EXP_LNKCTL, reg16);
+ pcie_capability_write_word(parent, PCI_EXP_LNKCTL, reg16);
/* Wait for link training end. Break out after waiting for timeout */
start_jiffies = jiffies;
for (;;) {
- pci_read_config_word(parent, ppos + PCI_EXP_LNKSTA, &reg16);
+ pcie_capability_read_word(parent, PCI_EXP_LNKSTA, &reg16);
if (!(reg16 & PCI_EXP_LNKSTA_LT))
break;
if (time_after(jiffies, start_jiffies + LINK_RETRAIN_TIMEOUT))
@@ -244,14 +242,11 @@ static void pcie_aspm_configure_common_clock(struct pcie_link_state *link)
return;
/* Training failed. Restore common clock configurations */
- dev_printk(KERN_ERR, &parent->dev,
- "ASPM: Could not configure common clock\n");
- list_for_each_entry(child, &linkbus->devices, bus_list) {
- cpos = pci_pcie_cap(child);
- pci_write_config_word(child, cpos + PCI_EXP_LNKCTL,
- child_reg[PCI_FUNC(child->devfn)]);
- }
- pci_write_config_word(parent, ppos + PCI_EXP_LNKCTL, parent_reg);
+ dev_err(&parent->dev, "ASPM: Could not configure common clock\n");
+ list_for_each_entry(child, &linkbus->devices, bus_list)
+ pcie_capability_write_word(child, PCI_EXP_LNKCTL,
+ child_reg[PCI_FUNC(child->devfn)]);
+ pcie_capability_write_word(parent, PCI_EXP_LNKCTL, parent_reg);
}
/* Convert L0s latency encoding to ns */
@@ -296,16 +291,14 @@ struct aspm_register_info {
static void pcie_get_aspm_reg(struct pci_dev *pdev,
struct aspm_register_info *info)
{
- int pos;
u16 reg16;
u32 reg32;
- pos = pci_pcie_cap(pdev);
- pci_read_config_dword(pdev, pos + PCI_EXP_LNKCAP, &reg32);
+ pcie_capability_read_dword(pdev, PCI_EXP_LNKCAP, &reg32);
info->support = (reg32 & PCI_EXP_LNKCAP_ASPMS) >> 10;
info->latency_encoding_l0s = (reg32 & PCI_EXP_LNKCAP_L0SEL) >> 12;
info->latency_encoding_l1 = (reg32 & PCI_EXP_LNKCAP_L1EL) >> 15;
- pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, &reg16);
+ pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &reg16);
info->enabled = reg16 & PCI_EXP_LNKCTL_ASPMC;
}
@@ -403,7 +396,7 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
* do ASPM for now.
*/
list_for_each_entry(child, &linkbus->devices, bus_list) {
- if (child->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE) {
+ if (pci_pcie_type(child) == PCI_EXP_TYPE_PCI_BRIDGE) {
link->aspm_disable = ASPM_STATE_ALL;
break;
}
@@ -411,17 +404,15 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
/* Get and check endpoint acceptable latencies */
list_for_each_entry(child, &linkbus->devices, bus_list) {
- int pos;
u32 reg32, encoding;
struct aspm_latency *acceptable =
&link->acceptable[PCI_FUNC(child->devfn)];
- if (child->pcie_type != PCI_EXP_TYPE_ENDPOINT &&
- child->pcie_type != PCI_EXP_TYPE_LEG_END)
+ if (pci_pcie_type(child) != PCI_EXP_TYPE_ENDPOINT &&
+ pci_pcie_type(child) != PCI_EXP_TYPE_LEG_END)
continue;
- pos = pci_pcie_cap(child);
- pci_read_config_dword(child, pos + PCI_EXP_DEVCAP, &reg32);
+ pcie_capability_read_dword(child, PCI_EXP_DEVCAP, &reg32);
/* Calculate endpoint L0s acceptable latency */
encoding = (reg32 & PCI_EXP_DEVCAP_L0S) >> 6;
acceptable->l0s = calc_l0s_acceptable(encoding);
@@ -435,13 +426,8 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
static void pcie_config_aspm_dev(struct pci_dev *pdev, u32 val)
{
- u16 reg16;
- int pos = pci_pcie_cap(pdev);
-
- pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, &reg16);
- reg16 &= ~0x3;
- reg16 |= val;
- pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, reg16);
+ pcie_capability_clear_and_set_word(pdev, PCI_EXP_LNKCTL,
+ PCI_EXP_LNKCTL_ASPMC, val);
}
static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state)
@@ -456,12 +442,12 @@ static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state)
return;
/* Convert ASPM state to upstream/downstream ASPM register state */
if (state & ASPM_STATE_L0S_UP)
- dwstream |= PCIE_LINK_STATE_L0S;
+ dwstream |= PCI_EXP_LNKCTL_ASPM_L0S;
if (state & ASPM_STATE_L0S_DW)
- upstream |= PCIE_LINK_STATE_L0S;
+ upstream |= PCI_EXP_LNKCTL_ASPM_L0S;
if (state & ASPM_STATE_L1) {
- upstream |= PCIE_LINK_STATE_L1;
- dwstream |= PCIE_LINK_STATE_L1;
+ upstream |= PCI_EXP_LNKCTL_ASPM_L1;
+ dwstream |= PCI_EXP_LNKCTL_ASPM_L1;
}
/*
* Spec 2.0 suggests all functions should be configured the
@@ -496,25 +482,32 @@ static void free_link_state(struct pcie_link_state *link)
static int pcie_aspm_sanity_check(struct pci_dev *pdev)
{
struct pci_dev *child;
- int pos;
u32 reg32;
+
/*
* Some functions in a slot might not all be PCIe functions,
* very strange. Disable ASPM for the whole slot
*/
list_for_each_entry(child, &pdev->subordinate->devices, bus_list) {
- pos = pci_pcie_cap(child);
- if (!pos)
+ if (!pci_is_pcie(child))
return -EINVAL;
+
+ /*
+ * If ASPM is disabled then we're not going to change
+ * the BIOS state. It's safe to continue even if it's a
+ * pre-1.1 device
+ */
+
+ if (aspm_disabled)
+ continue;
+
/*
* Disable ASPM for pre-1.1 PCIe device, we follow MS to use
* RBER bit to determine if a function is 1.1 version device
*/
- pci_read_config_dword(child, pos + PCI_EXP_DEVCAP, &reg32);
+ pcie_capability_read_dword(child, PCI_EXP_DEVCAP, &reg32);
if (!(reg32 & PCI_EXP_DEVCAP_RBER) && !aspm_force) {
- dev_printk(KERN_INFO, &child->dev, "disabling ASPM"
- " on pre-1.1 PCIe device. You can enable it"
- " with 'pcie_aspm=force'\n");
+ dev_info(&child->dev, "disabling ASPM on pre-1.1 PCIe device. You can enable it with 'pcie_aspm=force'\n");
return -EINVAL;
}
}
@@ -532,7 +525,7 @@ static struct pcie_link_state *alloc_pcie_link_state(struct pci_dev *pdev)
INIT_LIST_HEAD(&link->children);
INIT_LIST_HEAD(&link->link);
link->pdev = pdev;
- if (pdev->pcie_type == PCI_EXP_TYPE_DOWNSTREAM) {
+ if (pci_pcie_type(pdev) == PCI_EXP_TYPE_DOWNSTREAM) {
struct pcie_link_state *parent;
parent = pdev->bus->parent->self->link_state;
if (!parent) {
@@ -555,7 +548,7 @@ static struct pcie_link_state *alloc_pcie_link_state(struct pci_dev *pdev)
/*
* pcie_aspm_init_link_state: Initiate PCI express link state.
- * It is called after the pcie and its children devices are scaned.
+ * It is called after the pcie and its children devices are scanned.
* @pdev: the root port or switch downstream port
*/
void pcie_aspm_init_link_state(struct pci_dev *pdev)
@@ -563,14 +556,17 @@ void pcie_aspm_init_link_state(struct pci_dev *pdev)
struct pcie_link_state *link;
int blacklist = !!pcie_aspm_sanity_check(pdev);
- if (aspm_disabled || !pci_is_pcie(pdev) || pdev->link_state)
+ if (!aspm_support_enabled)
+ return;
+
+ if (!pci_is_pcie(pdev) || pdev->link_state)
return;
- if (pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
- pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM)
+ if (pci_pcie_type(pdev) != PCI_EXP_TYPE_ROOT_PORT &&
+ pci_pcie_type(pdev) != PCI_EXP_TYPE_DOWNSTREAM)
return;
/* VIA has a strange chipset, root port is under a bridge */
- if (pdev->pcie_type == PCI_EXP_TYPE_ROOT_PORT &&
+ if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT &&
pdev->bus->self)
return;
@@ -627,8 +623,8 @@ static void pcie_update_aspm_capable(struct pcie_link_state *root)
if (link->root != root)
continue;
list_for_each_entry(child, &linkbus->devices, bus_list) {
- if ((child->pcie_type != PCI_EXP_TYPE_ENDPOINT) &&
- (child->pcie_type != PCI_EXP_TYPE_LEG_END))
+ if ((pci_pcie_type(child) != PCI_EXP_TYPE_ENDPOINT) &&
+ (pci_pcie_type(child) != PCI_EXP_TYPE_LEG_END))
continue;
pcie_aspm_check_latency(child);
}
@@ -641,11 +637,7 @@ void pcie_aspm_exit_link_state(struct pci_dev *pdev)
struct pci_dev *parent = pdev->bus->self;
struct pcie_link_state *link, *root, *parent_link;
- if (aspm_disabled || !pci_is_pcie(pdev) ||
- !parent || !parent->link_state)
- return;
- if ((parent->pcie_type != PCI_EXP_TYPE_ROOT_PORT) &&
- (parent->pcie_type != PCI_EXP_TYPE_DOWNSTREAM))
+ if (!parent || !parent->link_state)
return;
down_read(&pci_bus_sem);
@@ -685,8 +677,8 @@ void pcie_aspm_pm_state_change(struct pci_dev *pdev)
if (aspm_disabled || !pci_is_pcie(pdev) || !link)
return;
- if ((pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT) &&
- (pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM))
+ if ((pci_pcie_type(pdev) != PCI_EXP_TYPE_ROOT_PORT) &&
+ (pci_pcie_type(pdev) != PCI_EXP_TYPE_DOWNSTREAM))
return;
/*
* Devices changed PM state, we should recheck if latency
@@ -700,24 +692,58 @@ void pcie_aspm_pm_state_change(struct pci_dev *pdev)
up_read(&pci_bus_sem);
}
-/*
- * pci_disable_link_state - disable pci device's link state, so the link will
- * never enter specific states
- */
-void pci_disable_link_state(struct pci_dev *pdev, int state)
+void pcie_aspm_powersave_config_link(struct pci_dev *pdev)
+{
+ struct pcie_link_state *link = pdev->link_state;
+
+ if (aspm_disabled || !pci_is_pcie(pdev) || !link)
+ return;
+
+ if (aspm_policy != POLICY_POWERSAVE)
+ return;
+
+ if ((pci_pcie_type(pdev) != PCI_EXP_TYPE_ROOT_PORT) &&
+ (pci_pcie_type(pdev) != PCI_EXP_TYPE_DOWNSTREAM))
+ return;
+
+ down_read(&pci_bus_sem);
+ mutex_lock(&aspm_lock);
+ pcie_config_aspm_path(link);
+ pcie_set_clkpm(link, policy_to_clkpm_state(link));
+ mutex_unlock(&aspm_lock);
+ up_read(&pci_bus_sem);
+}
+
+static void __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem,
+ bool force)
{
struct pci_dev *parent = pdev->bus->self;
struct pcie_link_state *link;
- if (aspm_disabled || !pci_is_pcie(pdev))
+ if (!pci_is_pcie(pdev))
return;
- if (pdev->pcie_type == PCI_EXP_TYPE_ROOT_PORT ||
- pdev->pcie_type == PCI_EXP_TYPE_DOWNSTREAM)
+
+ if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT ||
+ pci_pcie_type(pdev) == PCI_EXP_TYPE_DOWNSTREAM)
parent = pdev;
if (!parent || !parent->link_state)
return;
- down_read(&pci_bus_sem);
+ /*
+ * A driver requested that ASPM be disabled on this device, but
+ * if we don't have permission to manage ASPM (e.g., on ACPI
+ * systems we have to observe the FADT ACPI_FADT_NO_ASPM bit and
+ * the _OSC method), we can't honor that request. Windows has
+ * a similar mechanism using "PciASPMOptOut", which is also
+ * ignored in this situation.
+ */
+ if (aspm_disabled && !force) {
+ dev_warn(&pdev->dev, "can't disable ASPM; OS doesn't have ASPM control\n");
+ return;
+ }
+
+ if (sem)
+ down_read(&pci_bus_sem);
mutex_lock(&aspm_lock);
link = parent->link_state;
if (state & PCIE_LINK_STATE_L0S)
@@ -731,15 +757,56 @@ void pci_disable_link_state(struct pci_dev *pdev, int state)
pcie_set_clkpm(link, 0);
}
mutex_unlock(&aspm_lock);
- up_read(&pci_bus_sem);
+ if (sem)
+ up_read(&pci_bus_sem);
+}
+
+void pci_disable_link_state_locked(struct pci_dev *pdev, int state)
+{
+ __pci_disable_link_state(pdev, state, false, false);
+}
+EXPORT_SYMBOL(pci_disable_link_state_locked);
+
+/**
+ * pci_disable_link_state - Disable device's link state, so the link will
+ * never enter specific states. Note that if the BIOS didn't grant ASPM
+ * control to the OS, this does nothing because we can't touch the LNKCTL
+ * register.
+ *
+ * @pdev: PCI device
+ * @state: ASPM link state to disable
+ */
+void pci_disable_link_state(struct pci_dev *pdev, int state)
+{
+ __pci_disable_link_state(pdev, state, true, false);
}
EXPORT_SYMBOL(pci_disable_link_state);
+void pcie_clear_aspm(struct pci_bus *bus)
+{
+ struct pci_dev *child;
+
+ if (aspm_force)
+ return;
+
+ /*
+ * Clear any ASPM setup that the firmware has carried out on this bus
+ */
+ list_for_each_entry(child, &bus->devices, bus_list) {
+ __pci_disable_link_state(child, PCIE_LINK_STATE_L0S |
+ PCIE_LINK_STATE_L1 |
+ PCIE_LINK_STATE_CLKPM,
+ false, true);
+ }
+}
+
static int pcie_aspm_set_policy(const char *val, struct kernel_param *kp)
{
int i;
struct pcie_link_state *link;
+ if (aspm_disabled)
+ return -EPERM;
for (i = 0; i < ARRAY_SIZE(policy_str); i++)
if (!strncmp(val, policy_str[i], strlen(policy_str[i])))
break;
@@ -794,6 +861,8 @@ static ssize_t link_state_store(struct device *dev,
struct pcie_link_state *link, *root = pdev->link_state->root;
u32 val = buf[0] - '0', state = 0;
+ if (aspm_disabled)
+ return -EPERM;
if (n < 1 || val > 3)
return -EINVAL;
@@ -855,8 +924,8 @@ void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev)
struct pcie_link_state *link_state = pdev->link_state;
if (!pci_is_pcie(pdev) ||
- (pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
- pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM) || !link_state)
+ (pci_pcie_type(pdev) != PCI_EXP_TYPE_ROOT_PORT &&
+ pci_pcie_type(pdev) != PCI_EXP_TYPE_DOWNSTREAM) || !link_state)
return;
if (link_state->aspm_support)
@@ -872,8 +941,8 @@ void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev)
struct pcie_link_state *link_state = pdev->link_state;
if (!pci_is_pcie(pdev) ||
- (pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
- pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM) || !link_state)
+ (pci_pcie_type(pdev) != PCI_EXP_TYPE_ROOT_PORT &&
+ pci_pcie_type(pdev) != PCI_EXP_TYPE_DOWNSTREAM) || !link_state)
return;
if (link_state->aspm_support)
@@ -888,11 +957,13 @@ void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev)
static int __init pcie_aspm_disable(char *str)
{
if (!strcmp(str, "off")) {
+ aspm_policy = POLICY_DEFAULT;
aspm_disabled = 1;
+ aspm_support_enabled = false;
printk(KERN_INFO "PCIe ASPM is disabled\n");
} else if (!strcmp(str, "force")) {
aspm_force = 1;
- printk(KERN_INFO "PCIe ASPM is forcedly enabled\n");
+ printk(KERN_INFO "PCIe ASPM is forcibly enabled\n");
}
return 1;
}
@@ -901,19 +972,20 @@ __setup("pcie_aspm=", pcie_aspm_disable);
void pcie_no_aspm(void)
{
- if (!aspm_force)
+ /*
+ * Disabling ASPM is intended to prevent the kernel from modifying
+ * existing hardware state, not to clear existing state. To that end:
+ * (a) set policy to POLICY_DEFAULT in order to avoid changing state
+ * (b) prevent userspace from changing policy
+ */
+ if (!aspm_force) {
+ aspm_policy = POLICY_DEFAULT;
aspm_disabled = 1;
+ }
}
-/**
- * pcie_aspm_enabled - is PCIe ASPM enabled?
- *
- * Returns true if ASPM has not been disabled by the command-line option
- * pcie_aspm=off.
- **/
-int pcie_aspm_enabled(void)
+bool pcie_aspm_support_enabled(void)
{
- return !aspm_disabled;
+ return aspm_support_enabled;
}
-EXPORT_SYMBOL(pcie_aspm_enabled);
-
+EXPORT_SYMBOL(pcie_aspm_support_enabled);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2025-11-03 18:27:20 +0000