From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B0E29559308; Mon, 31 Aug 2026 13:47:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788184043; cv=none; b=FmIu+Oc7OvPP90hoLa6W9EJKBoTltJCM4RScOHhr/NZwRA28zxhiwJoqMp29YGNXVCx9kAg9obbK7k9wHMk9VkTZwUnZNWYN29dPRnsmBINebOskZ7CHGW2wN6kpGAPe9wbxbFn/jn0JX2dQ8IoLJrdkB04hJ9BH0S/Qo1196Qk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788184043; c=relaxed/simple; bh=/Xsz5I6HkmNkamVyJWHhNOtRzjEbRhgnJA3VZuGRYEg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=AoL1vFFkdaeHcVgLSPvmwInE9A7cVMVSGf2ZiLGaXguRxo+ZdNxMY5LJUxLsf3NkW4WuRx9CWlk0uk/HSxO2F2ny1x8SfaSGmTBa3jLRwkJMyKzhcOg1vQ2tKLqTb+rx9a1CET0AyTRQJwkacjNx8IxVA1beJ00RjM8InOLJifg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EShJasyn; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="EShJasyn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1B6811F000E9; Mon, 31 Aug 2026 13:47:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788184039; bh=qraHHyWGPOawjxx5eJlLEGU9p/zi01bi/ditLojLt6Y=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=EShJasynCBkr+KbF6ZerY4j3DIe3hAEBDBfnWuXY+yMZOr3SEZ8QG6uq5/nbU33qT GpOBEdd0hnymbWSqJK0O2/A0ADRoeukPyg0aNSZ8jKMUkCJqd9U/ASzMbPe4DZs+ek b6G7RY4645qIm+NU8xF8RqEYI1obPNEf6z33Gze3mtjD+oVwSPkFvjSxjr2K/HGk5L dFBjfi7ZY8IdvR2pBc7JBspCkeIbz9QvVS9bKyb2B991/TsKPZY8sGACU9++Hql0p4 EKjlb8WWDDSjWBOHmp7fsP+HgI77v7cIeUr++1UhqzGeDHB1oCbx/tHTeIc1jO967K 5JnaCmVV5Wblg== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Kiran K , Luiz Augusto von Dentz , Sasha Levin , marcel@holtmann.org, luiz.dentz@gmail.com, linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH AUTOSEL 6.18-6.12] Bluetooth: btintel_pcie: Add 50 ms delay before MAC init on BlazarIW Date: Mon, 31 Aug 2026 09:28:03 -0400 Message-ID: <20260831133314.4125787-455-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260831133314.4125787-1-sashal@kernel.org> References: <20260831133314.4125787-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.18.48 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Kiran K [ Upstream commit 4d62d88e7ae6dcecd9a8c70a045a6c6c64bf3b52 ] 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 Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin --- LLM Generated explanations, may be completely bogus: The background checks finished and match the earlier analysis: 1. **Commit search** — The BlazarIW 50 ms delay patch is **not in this local tree**. A `git log --grep="50 ms delay"` only turned up unrelated delay commits in other subsystems (xprtrdma, hci_qca, drm). 2. **BlazarIW support** — Device `0x4D76` landed via `6053b532d345b` and is present from the **v6.17/v6.18** era onward. It is **not** in v6.12, which fits evaluating this only for the checked-out **v6.18.44** tree. That leaves the conclusion unchanged: backport **YES** for this tree — BlazarIW is supported here, but the MAC-init timing fix is still missing. 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 d0aa1666d6ac6..c0441541c0862 100644 --- a/drivers/bluetooth/btintel_pcie.c +++ b/drivers/bluetooth/btintel_pcie.c @@ -740,6 +740,11 @@ 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. @@ -759,6 +764,14 @@ 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. */ -- 2.53.0