* [PATCH v1] Bluetooth: btintel_pcie: Add 50 ms delay before MAC init on BlazarIW
@ 2026-06-06 0:36 Kiran K
2026-06-06 0:44 ` [v1] " bluez.test.bot
0 siblings, 1 reply; 2+ messages in thread
From: Kiran K @ 2026-06-06 0:36 UTC (permalink / raw)
To: linux-bluetooth
Cc: ravishankar.srivatsa, chethan.tumkur.narayan,
chandrashekar.devegowda, Kiran K
On BlazarIW, fast restart cycles fail because the D0 entry to MAC
init does not complete in time. As a result, MAC initialization
does not proceed and the controller fails to transition past the
ROM boot stage.
Add a 50 ms delay (worst case as per HW analysis) before doing MAC
init in btintel_pcie_enable_bt() so the shared hardware reset flow
has time to complete. The delay is gated on the BlazarIW PCI device
id 0x4D76 so other Intel BT PCIe controllers are unaffected.
Signed-off-by: Kiran K <kiran.k@intel.com>
---
drivers/bluetooth/btintel_pcie.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/drivers/bluetooth/btintel_pcie.c b/drivers/bluetooth/btintel_pcie.c
index 2baef130d101..b09878d71025 100644
--- a/drivers/bluetooth/btintel_pcie.c
+++ b/drivers/bluetooth/btintel_pcie.c
@@ -799,6 +799,11 @@ static void btintel_pcie_dump_traces(struct hci_dev *hdev)
bt_dev_err(hdev, "Failed to dump traces: (%d)", ret);
}
+static bool btintel_pcie_is_blazariw(struct pci_dev *pdev)
+{
+ return pdev->device == 0x4D76;
+}
+
/* This function enables BT function by setting BTINTEL_PCIE_CSR_FUNC_CTRL_MAC_INIT bit in
* BTINTEL_PCIE_CSR_FUNC_CTRL_REG register and wait for MSI-X with
* BTINTEL_PCIE_MSIX_HW_INT_CAUSES_GP0.
@@ -818,6 +823,14 @@ static int btintel_pcie_enable_bt(struct btintel_pcie_data *data)
btintel_pcie_wr_reg32(data, BTINTEL_PCIE_CSR_CI_ADDR_MSB_REG,
(u64)data->ci_p_addr >> 32);
+ /* On BlazarIW, the D0 entry to MAC init does not complete in
+ * time. Wait 50 ms (worst case as per HW analysis) for the
+ * shared hardware reset flow to complete before proceeding with
+ * MAC init.
+ */
+ if (btintel_pcie_is_blazariw(data->pdev))
+ msleep(50);
+
/* Reset the cached value of boot stage. it is updated by the MSI-X
* gp0 interrupt handler.
*/
--
2.54.0
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