[SRU N][PATCH 1/1] PCI: pciehp: Retain Power Indicator bits for userspace indicators

[Michael Reed]

From: Blazej Kucman <blazej.kucman at intel.com>

BugLink: https://bugs.launchpad.net/bugs/2077287

The sysfs "attention" file normally controls the Slot Control Attention
Indicator with 0 (off), 1 (on), 2 (blink) settings.

576243b3f9ea ("PCI: pciehp: Allow exclusive userspace control of
indicators") added pciehp_set_raw_indicator_status() to allow userspace to
directly control all four bits in both the Attention Indicator and the
Power Indicator fields via the "attention" file.

This is used on Intel VMD bridges so utilities like "ledmon" can use sysfs
"attention" to control up to 16 indicators for NVMe device RAID status.

abaaac4845a0 ("PCI: hotplug: Use FIELD_GET/PREP()") broke this by masking
the sysfs data with PCI_EXP_SLTCTL_AIC, which discards the upper two bits
intended for the Power Indicator Control field (PCI_EXP_SLTCTL_PIC).

For NVMe devices behind an Intel VMD, ledmon settings that use the
PCI_EXP_SLTCTL_PIC bits, i.e., ATTENTION_REBUILD (0x5), ATTENTION_LOCATE
(0x7), ATTENTION_FAILURE (0xD), ATTENTION_OFF (0xF), no longer worked
correctly.

Mask with PCI_EXP_SLTCTL_AIC | PCI_EXP_SLTCTL_PIC to retain both the
Attention Indicator and the Power Indicator bits.

Fixes: abaaac4845a0 ("PCI: hotplug: Use FIELD_GET/PREP()")
Link: https://lore.kernel.org/r/20240722141440.7210-1-blazej.kucman@intel.com
Signed-off-by: Blazej Kucman <blazej.kucman at intel.com>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas at google.com>
Cc: stable at vger.kernel.org	# v6.7+
(cherry picked from commit 5560a612c20d3daacbf5da7913deefa5c31742f4)
Signed-off-by: Michael Reed <Michael.Reed at canonical.com>
---
 drivers/pci/hotplug/pciehp_hpc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index b1d0a1b3917d..9d3c249207c4 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -485,7 +485,9 @@ int pciehp_set_raw_indicator_status(struct hotplug_slot *hotplug_slot,
 	struct pci_dev *pdev = ctrl_dev(ctrl);
 
 	pci_config_pm_runtime_get(pdev);
-	pcie_write_cmd_nowait(ctrl, FIELD_PREP(PCI_EXP_SLTCTL_AIC, status),
+
+	/* Attention and Power Indicator Control bits are supported */
+	pcie_write_cmd_nowait(ctrl, FIELD_PREP(PCI_EXP_SLTCTL_AIC | PCI_EXP_SLTCTL_PIC, status),
 			      PCI_EXP_SLTCTL_AIC | PCI_EXP_SLTCTL_PIC);
 	pci_config_pm_runtime_put(pdev);
 	return 0;
-- 
2.34.1