If CONFIG_PCIEASPM_DEBUG is set, then pci devices have a link_state
attribute. Reading that attribute shows the state as a bit mask: 1
means L0S upstream, 2 means L0S downstream, and 4 means L1.
Oddly, writing to link_state is inconsistent and gets translated,
leading to mysterious results in which the value you store isn't
comparable the value you load back out.
Fix it by making link_state_store match link_state_show.
Signed-off-by: Andy Lutomirski <luto@xxxxxxxxxx>
---
drivers/pci/pcie/aspm.c | 12 +++---------
1 file changed, 3 insertions(+), 9 deletions(-)
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 317e3558a35e..e543dac8e3f2 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -834,22 +834,16 @@ static ssize_t link_state_store(struct device *dev,
{
struct pci_dev *pdev = to_pci_dev(dev);
struct pcie_link_state *link, *root = pdev->link_state->root;
- u32 val, state = 0;
+ u32 state;
- if (kstrtouint(buf, 10, &val))
+ if (kstrtouint(buf, 10, &state))
return -EINVAL;
if (aspm_disabled)
return -EPERM;
- if (n < 1 || val > 3)
+ if ((state & ~ASPM_STATE_ALL) != 0)
return -EINVAL;
- /* Convert requested state to ASPM state */
- if (val & PCIE_LINK_STATE_L0S)
- state |= ASPM_STATE_L0S;
- if (val & PCIE_LINK_STATE_L1)
- state |= ASPM_STATE_L1;
-
down_read(&pci_bus_sem);
mutex_lock(&aspm_lock);
list_for_each_entry(link, &link_list, sibling) {
--
2.5.0
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