[PATCH v5 09/21] wifi: mt76: mt7925: disable ASPM and runtime PM for MT7927

Sean Wang
2026-04-25T19:51:21Z

From: Javier Tia <floss@jetm.me>

Disable PCIe ASPM unconditionally for MT7927. The CONNINFRA power
domain and WFDMA register access are unreliable with PCIe L1 active,
causing throughput to drop from 1+ Gbps to ~200 Mbps.

Disable runtime PM and deep sleep for MT7927. The combo chip shares
a CONNINFRA power domain between WiFi (PCIe) and BT (USB).
SET_OWN/CLR_OWN transitions on the LPCTL register crash the BT
firmware, requiring a full power cycle to recover. PM enablement will
be addressed in a follow-up once safe power state transitions are
determined.

Reviewed-by: Sean Wang <sean.wang@mediatek.com>
Signed-off-by: Javier Tia <floss@jetm.me>
---
drivers/net/wireless/mediatek/mt76/mt7925/init.c | 3 ++-
drivers/net/wireless/mediatek/mt76/mt7925/pci.c | 6 ++++--
2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/init.c b/drivers/net/wireless/mediatek/mt76/mt7925/init.c
index c0c5cb9aff75..a8c2ca7c0efc 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/init.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/init.c
@@ -232,7 +232,8 @@ int mt7925_register_device(struct mt792x_dev *dev)
dev->pm.idle_timeout = MT792x_PM_TIMEOUT;
dev->pm.stats.last_wake_event = jiffies;
dev->pm.stats.last_doze_event = jiffies;
- if (!mt76_is_usb(&dev->mt76)) {
+ /* MT7927: runtime PM crashes BT firmware on the shared CONNINFRA domain */
+ if (!mt76_is_usb(&dev->mt76) && !is_mt7927(&dev->mt76)) {
dev->pm.enable_user = true;
dev->pm.enable = true;
dev->pm.ds_enable_user = true;
diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/pci.c b/drivers/net/wireless/mediatek/mt76/mt7925/pci.c
index 604c0e9ae7ba..1f05c212be02 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/pci.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/pci.c
@@ -350,7 +350,10 @@ static int mt7925_pci_probe(struct pci_dev *pdev,
if (ret)
goto err_free_pci_vec;

- if (mt7925_disable_aspm)
+ is_mt7927_hw = (pdev->device == 0x6639 || pdev->device == 0x7927);
+
+ /* MT7927: ASPM L1 causes unreliable WFDMA register access */
+ if (mt7925_disable_aspm || is_mt7927_hw)
mt76_pci_disable_aspm(pdev);

ops = mt792x_get_mac80211_ops(&pdev->dev, &mt7925_ops,
@@ -371,7 +374,6 @@ static int mt7925_pci_probe(struct pci_dev *pdev,
dev = container_of(mdev, struct mt792x_dev, mt76);
dev->fw_features = features;
dev->hif_ops = &mt7925_pcie_ops;
- is_mt7927_hw = (pdev->device == 0x6639 || pdev->device == 0x7927);
dev->irq_map = is_mt7927_hw ? &mt7927_irq_map : &irq_map;
mt76_mmio_init(&dev->mt76, pcim_iomap_table(pdev)[0]);
tasklet_init(&mdev->irq_tasklet, mt792x_irq_tasklet, (unsigned long)dev);
--
2.43.0