On 30.04.2019 19:53, Bjorn Helgaas wrote:
> On Sat, Apr 13, 2019 at 11:12:41AM +0200, Heiner Kallweit wrote:
>> Background of this extension is a problem with the r8169 network driver.
>> Several combinations of board chipsets and network chip versions have
>> problems if ASPM is enabled, therefore we have to disable ASPM per
>> default. However especially on notebooks ASPM can provide significant
>> power-saving, therefore we want to give users the option to enable
>> ASPM. With the new sysfs attribute users can control which ASPM
>> link-states are disabled.
>
>> +void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev);
>> +void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev);
>> #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) { }
>> -#endif
>> -
>> -#ifdef CONFIG_PCIEASPM_DEBUG
>> -void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev);
>> -void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev);
>> -#else
>
> I like the idea of exposing these sysfs control files all the time,
> instead of only when CONFIG_PCIEASPM_DEBUG=y, but I think when we do
> that, we should put the files at the downstream end of the link (e.g.,
> an endpoint) instead of at the upstream end (e.g., a root port or
> switch downstream port). We had some conversation about this here:
>
> https://lore.kernel.org/lkml/20180727202619.GD173328@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
>
> Doing it at the downstream end would require more changes, of course,
> and probably raises some locking issues, but I think we have a small
> window of opportunity here where we can tweak the sysfs structure
> before we're committed to supporting something forever.
>
> Bjorn
>
Here comes an updated version of patch 3. Unfortunately my test systems
don't allow OS ASPM control. At least the sysfs files are created for
the right devices (endpoints), and the attribute can be properly
controlled.
---
drivers/pci/pci.h | 8 +-
drivers/pci/pcie/aspm.c | 171 +++++++++++++++++++++++++++++++++++++++-
2 files changed, 171 insertions(+), 8 deletions(-)
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 9cb99380c..06642b7de 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -499,17 +499,13 @@ 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);
+void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev);
+void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev);
#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) { }
-#endif
-
-#ifdef CONFIG_PCIEASPM_DEBUG
-void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev);
-void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev);
-#else
static inline void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev) { }
static inline void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev) { }
#endif
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 7847be38e..f73539e5b 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -42,6 +42,8 @@
#define ASPM_STATE_ALL (ASPM_STATE_L0S | ASPM_STATE_L1 | \
ASPM_STATE_L1SS)
+static const char power_group[] = "power";
+
struct aspm_latency {
u32 l0s; /* L0s latency (nsec) */
u32 l1; /* L1 latency (nsec) */
@@ -1251,38 +1253,203 @@ static ssize_t clk_ctl_store(struct device *dev,
static DEVICE_ATTR_RW(link_state);
static DEVICE_ATTR_RW(clk_ctl);
+#endif
+
+struct aspm_sysfs_state {
+ const char *name;
+ int disable_mask;
+};
+
+static const struct aspm_sysfs_state aspm_sysfs_states[] = {
+ { "L0S", ASPM_STATE_L0S },
+ { "L1", ASPM_STATE_L1 },
+ { "L1.1", ASPM_STATE_L1_1_MASK },
+ { "L1.2", ASPM_STATE_L1_2_MASK },
+};
+
+static struct pcie_link_state *aspm_get_parent_link(struct pci_dev *pdev)
+{
+ struct pci_dev *parent = pdev->bus->self;
+
+ if (pdev->has_secondary_link)
+ parent = pdev;
+
+ return parent ? parent->link_state : NULL;
+}
+
+static ssize_t aspm_disable_link_state_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct pci_dev *pdev = to_pci_dev(dev);
+ struct pcie_link_state *link;
+ int len = 0, i;
+
+ link = aspm_get_parent_link(pdev);
+ if (!link)
+ return -EOPNOTSUPP;
+
+ mutex_lock(&aspm_lock);
+
+ for (i = 0; i < ARRAY_SIZE(aspm_sysfs_states); i++) {
+ const struct aspm_sysfs_state *st = aspm_sysfs_states + i;
+
+ if (link->aspm_disable & st->disable_mask)
+ len += scnprintf(buf + len, PAGE_SIZE - len, "[%s] ",
+ st->name);
+ else
+ len += scnprintf(buf + len, PAGE_SIZE - len, "%s ",
+ st->name);
+ }
+
+ if (link->clkpm_disable)
+ len += scnprintf(buf + len, PAGE_SIZE - len, "[CLKPM] ");
+ else
+ len += scnprintf(buf + len, PAGE_SIZE - len, "CLKPM ");
+
+ mutex_unlock(&aspm_lock);
+
+ len += scnprintf(buf + len, PAGE_SIZE - len, "\n");
+
+ return len;
+}
+
+static ssize_t aspm_disable_link_state_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct pci_dev *pdev = to_pci_dev(dev);
+ struct pcie_link_state *link;
+ char *buftmp = (char *)buf, *tok;
+ unsigned int disable_aspm, disable_clkpm;
+ bool first = true, add;
+ int err = 0, i;
+
+ if (aspm_disabled)
+ return -EPERM;
+
+ link = aspm_get_parent_link(pdev);
+ if (!link)
+ return -EOPNOTSUPP;
+
+ down_read(&pci_bus_sem);
+ mutex_lock(&aspm_lock);
+
+ disable_aspm = link->aspm_disable;
+ disable_clkpm = link->clkpm_disable;
+
+ while ((tok = strsep(&buftmp, " \n")) != NULL) {
+ bool found = false;
+
+ if (!*tok)
+ continue;
+
+ if (first) {
+ if (!strcasecmp(tok, "none")) {
+ disable_aspm = 0;
+ disable_clkpm = 0;
+ break;
+ }
+ if (!strcasecmp(tok, "all")) {
+ disable_aspm = ASPM_STATE_ALL;
+ disable_clkpm = 1;
+ break;
+ }
+ first = false;
+ }
+
+ if (*tok != '+' && *tok != '-') {
+ err = -EINVAL;
+ goto out;
+ }
+
+ add = *tok++ == '+';
+
+ for (i = 0; i < ARRAY_SIZE(aspm_sysfs_states); i++) {
+ const struct aspm_sysfs_state *st =
+ aspm_sysfs_states + i;
+
+ if (!strcasecmp(tok, st->name)) {
+ if (add)
+ disable_aspm |= st->disable_mask;
+ else
+ disable_aspm &= ~st->disable_mask;
+ found = true;
+ break;
+ }
+ }
+
+ if (!found && !strcasecmp(tok, "clkpm")) {
+ disable_clkpm = add ? 1 : 0;
+ found = true;
+ }
+
+ if (!found) {
+ err = -EINVAL;
+ goto out;
+ }
+ }
+
+ if (disable_aspm & ASPM_STATE_L1)
+ disable_aspm |= ASPM_STATE_L1SS;
+
+ link->aspm_disable = disable_aspm;
+ link->clkpm_disable = disable_clkpm;
+
+ pcie_config_aspm_link(link, policy_to_aspm_state(link));
+ pcie_set_clkpm(link, policy_to_clkpm_state(link));
+out:
+ mutex_unlock(&aspm_lock);
+ up_read(&pci_bus_sem);
+
+ return err ?: len;
+}
+
+static DEVICE_ATTR_RW(aspm_disable_link_state);
-static char power_group[] = "power";
void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev)
{
struct pcie_link_state *link_state = pdev->link_state;
+ if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ENDPOINT &&
+ aspm_get_parent_link(pdev))
+ sysfs_add_file_to_group(&pdev->dev.kobj,
+ &dev_attr_aspm_disable_link_state.attr, power_group);
+
if (!link_state)
return;
+#ifdef CONFIG_PCIEASPM_DEBUG
if (link_state->aspm_support)
sysfs_add_file_to_group(&pdev->dev.kobj,
&dev_attr_link_state.attr, power_group);
if (link_state->clkpm_capable)
sysfs_add_file_to_group(&pdev->dev.kobj,
&dev_attr_clk_ctl.attr, power_group);
+#endif
}
void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev)
{
struct pcie_link_state *link_state = pdev->link_state;
+ if (pci_pcie_type(pdev) == PCI_EXP_TYPE_ENDPOINT &&
+ aspm_get_parent_link(pdev))
+ sysfs_remove_file_from_group(&pdev->dev.kobj,
+ &dev_attr_aspm_disable_link_state.attr, power_group);
+
if (!link_state)
return;
+#ifdef CONFIG_PCIEASPM_DEBUG
if (link_state->aspm_support)
sysfs_remove_file_from_group(&pdev->dev.kobj,
&dev_attr_link_state.attr, power_group);
if (link_state->clkpm_capable)
sysfs_remove_file_from_group(&pdev->dev.kobj,
&dev_attr_clk_ctl.attr, power_group);
-}
#endif
+}
static int __init pcie_aspm_disable(char *str)
{
--
2.21.0
