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Commit 57d86a04 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Bjorn Helgaas
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PCI/ASPM: Make sysfs link_state_store() consistent with link_state_show() 



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().

[bhelgaas: Check "aspm_disabled" *before* validating input.  When
"aspm_disabled" is set, this changes the error for invalid input from
-EINVAL to -EPERM.]

Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent 1ec21837

drivers/pci/pcie/aspm.c

+5 −11
Original line number Original line Diff line number Diff line
@@ -834,21 +834,15 @@ static ssize_t link_state_store(struct device *dev, 
{

{

	struct pci_dev *pdev = to_pci_dev(dev);

	struct pci_dev *pdev = to_pci_dev(dev);

	struct pcie_link_state *link, *root = pdev->link_state->root;

	struct pcie_link_state *link, *root = pdev->link_state->root;

	u32 val, state = 0;

	u32 state;



	if (kstrtouint(buf, 10, &val))

		return -EINVAL;





	if (aspm_disabled)

	if (aspm_disabled)

		return -EPERM;

		return -EPERM;

	if (n < 1 || val > 3)

		return -EINVAL;





	/* Convert requested state to ASPM state */

	if (kstrtouint(buf, 10, &state))

	if (val & PCIE_LINK_STATE_L0S)

		return -EINVAL;

		state |= ASPM_STATE_L0S;

	if ((state & ~ASPM_STATE_ALL) != 0)

	if (val & PCIE_LINK_STATE_L1)

		return -EINVAL;

		state |= ASPM_STATE_L1;





	down_read(&pci_bus_sem);

	down_read(&pci_bus_sem);

	mutex_lock(&aspm_lock);

	mutex_lock(&aspm_lock);