[PATCH v3 12/13] wifi: mt76: mt7925: disable ASPM and runtime PM for MT7927

[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.

Signed-off-by: Javier Tia <floss@jetm.me>
---
 drivers/net/wireless/mediatek/mt76/mt7925/init.c | 6 +++++-
 drivers/net/wireless/mediatek/mt76/mt7925/pci.c  | 9 +++++++--
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/init.c b/drivers/net/wireless/mediatek/mt76/mt7925/init.c
index c4c99380f5b5..89140fc6a2b6 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/init.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/init.c
@@ -243,7 +243,11 @@ 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 disabled. The combo chip shares a CONNINFRA
+	 * power domain between WiFi (PCIe) and BT (USB). SET_OWN/CLR_OWN
+	 * transitions on the LPCTL register crash BT firmware.
+	 */
+	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 393d9f408b84..693e08f35d68 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/pci.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/pci.c
@@ -530,7 +530,13 @@ 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: CONNINFRA power domain and WFDMA register access are
+	 * unreliable with PCIe L1 active, causing throughput to drop
+	 * from 1+ Gbps to ~200 Mbps. Disable ASPM unconditionally.
+	 */
+	if (mt7925_disable_aspm || is_mt7927_hw)
 		mt76_pci_disable_aspm(pdev);
 
 	ops = mt792x_get_mac80211_ops(&pdev->dev, &mt7925_ops,
@@ -562,7 +568,6 @@ 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;
 	dev->dma_config = is_mt7927_hw ? &mt7927_dma_cfg : &mt7925_dma_cfg;
 	mt76_mmio_init(&dev->mt76, pcim_iomap_table(pdev)[0]);

-- 
2.53.0