diff mbox series

[6/7] ath11k: do not restore ASPM in case of single MSI vector

Message ID 20211026041722.5271-1-bqiang@codeaurora.org (mailing list archive)
State Accepted
Commit 915a081ff307d61d6551d6c16b542e03775353c4
Delegated to: Kalle Valo
Headers show
Series ath11k: support one MSI vector | expand

Commit Message

Baochen Qiang Oct. 26, 2021, 4:17 a.m. UTC 
From: Carl Huang <cjhuang@codeaurora.org>

Current code enables ASPM by default, it allows MHI to enter M2 state.
In case of one MSI vector, system hang is observed if ath11k does MHI
register reading in this state. The issue was reported on Dell XPS 13
9310 but is seen also on XPS 15 and XPS 17 laptops.

The workaround here is to prevent MHI from entering M2 state, this can
be done by disabling ASPM if only one MSI vector is used. When using 32
vectors ASPM is enabled as before.

Tested-on: QCA6390 hw2.0 PCI WLAN.HST.1.0.1-01740-QCAHSTSWPLZ_V2_TO_X86-1

Signed-off-by: Carl Huang <cjhuang@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Baochen Qiang <bqiang@codeaurora.org>
---
 drivers/net/wireless/ath/ath11k/pci.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/net/wireless/ath/ath11k/pci.c b/drivers/net/wireless/ath/ath11k/pci.c
index 0a87d00a3a23..b450b4ed35d1 100644
--- a/drivers/net/wireless/ath/ath11k/pci.c
+++ b/drivers/net/wireless/ath/ath11k/pci.c
@@ -1220,7 +1220,13 @@  static int ath11k_pci_start(struct ath11k_base *ab)
 
 	set_bit(ATH11K_PCI_FLAG_INIT_DONE, &ab_pci->flags);
 
-	ath11k_pci_aspm_restore(ab_pci);
+	/* TODO: for now don't restore ASPM in case of single MSI
+	 * vector as MHI register reading in M2 causes system hang.
+	 */
+	if (test_bit(ATH11K_PCI_FLAG_MULTI_MSI_VECTORS, &ab_pci->flags))
+		ath11k_pci_aspm_restore(ab_pci);
+	else
+		ath11k_info(ab, "leaving PCI ASPM disabled to avoid MHI M2 problems\n");
 
 	ath11k_pci_ce_irqs_enable(ab);
 	ath11k_ce_rx_post_buf(ab);