From 3fa4eb4f63e234d431e7063e8a1c85ed44ee2c7c Mon Sep 17 00:00:00 2001
From: davigamer987 <68574209+davigamer987@users.noreply.github.com>
Date: Thu, 31 Jul 2025 20:46:39 -0300
Subject: [PATCH] Introduce target patch to disable LOCAL_EXT_FEATURES only on
 BR8554 devices

Using quirks seems to be the correct approach for non compliant controllers, I've added the ID for the CM749 but I'm unsure if it's the same on the CM748 (No Antena) model

The driver still seems somewhat unstable as this device doesn't support some other commands, but it's better than nothing
---
 cm749.patch | 83 +++++++++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 71 insertions(+), 12 deletions(-)

diff --git a/cm749.patch b/cm749.patch
index 8556d8a..3955a8b 100644
--- a/cm749.patch
+++ b/cm749.patch
@@ -1,12 +1,71 @@
-diff -urpN linux-6.15.7.orig/net/bluetooth/hci_sync.c linux-6.15.7/net/bluetooth/hci_sync.c
---- linux-6.15.7.orig/net/bluetooth/hci_sync.c	2025-07-25 21:32:04.088796199 -0400
-+++ linux-6.15.7/net/bluetooth/hci_sync.c	2025-07-26 00:03:09.827219049 -0400
-@@ -3961,7 +3961,7 @@ static const struct hci_init_stage hci_i
- 	/* HCI_OP_READ_INQ_RSP_TX_POWER */
- 	HCI_INIT(hci_read_inq_rsp_tx_power_sync),
- 	/* HCI_OP_READ_LOCAL_EXT_FEATURES */
--	HCI_INIT(hci_read_local_ext_features_1_sync),
-+	/* HCI_INIT(hci_read_local_ext_features_1_sync), */
- 	/* HCI_OP_WRITE_AUTH_ENABLE */
- 	HCI_INIT(hci_write_auth_enable_sync),
- 	{}
+diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
+index 6f2fd043f..42b7eaecd 100644
+--- a/drivers/bluetooth/btusb.c
++++ b/drivers/bluetooth/btusb.c
+@@ -66,6 +66,7 @@ static struct usb_driver btusb_driver;
+ #define BTUSB_INTEL_BROKEN_INITIAL_NCMD BIT(25)
+ #define BTUSB_INTEL_NO_WBS_SUPPORT	BIT(26)
+ #define BTUSB_ACTIONS_SEMI		BIT(27)
++#define BTUSB_BROKEN_LOCAL_EXT_FEATURES BIT(28)
+ 
+ static const struct usb_device_id btusb_table[] = {
+ 	/* Generic Bluetooth USB device */
+@@ -801,6 +802,9 @@ static const struct usb_device_id quirks_table[] = {
+ 	/* Silicon Wave based devices */
+ 	{ USB_DEVICE(0x0c10, 0x0000), .driver_info = BTUSB_SWAVE },
+ 
++	/* Barrot BR8554 based devices */
++	{ USB_DEVICE(0x33fa, 0x0010), .driver_info = BTUSB_BROKEN_LOCAL_EXT_FEATURES },
++
+ 	{ }	/* Terminating entry */
+ };
+ 
+@@ -4070,6 +4074,16 @@ static int btusb_probe(struct usb_interface *intf,
+ 		data->isoc_ifnum = ifnum_base + 1;
+ 	}
+ 
++	/* Some Barrot controllers timeout when initializing local ext features */
++	if (id->driver_info & BTUSB_BROKEN_LOCAL_EXT_FEATURES) {
++		/*
++		* This flag is set for devices that are known to be non-compliant
++		* with the HCI spec, they timeout when initializing LOCAL_EXT features.
++		*/
++
++		hci_set_quirk(hdev, HCI_QUIRK_BROKEN_LOCAL_EXT_FEATURES);
++	}
++
+ 	if (IS_ENABLED(CONFIG_BT_HCIBTUSB_RTL) &&
+ 	    (id->driver_info & BTUSB_REALTEK)) {
+ 		btrtl_set_driver_name(hdev, btusb_driver.name);
+diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
+index f47dfb8b5..3f1e239ef 100644
+--- a/include/net/bluetooth/hci.h
++++ b/include/net/bluetooth/hci.h
+@@ -294,6 +294,13 @@ enum {
+ 	 */
+ 	HCI_QUIRK_BROKEN_MWS_TRANSPORT_CONFIG,
+ 
++	/*
++	* The Barrot BR8554 chip in some adapters like the (33fa:0010, rev 88.91)
++	* is non-compliant and fails the LOCAL_EXT_FEATURES HCI initialization command.
++	* Set a quirk to skip these commands.
++	*/
++	HCI_QUIRK_BROKEN_LOCAL_EXT_FEATURES,
++
+ 	/* When this quirk is set, max_page for local extended features
+ 	 * is set to 1, even if controller reports higher number. Some
+ 	 * controllers (e.g. RTL8723CS) report more pages, but they
+diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c
+index 0972167c1..8a0cdd23e 100644
+--- a/net/bluetooth/hci_sync.c
++++ b/net/bluetooth/hci_sync.c
+@@ -3945,6 +3945,9 @@ static int hci_read_local_ext_features_sync(struct hci_dev *hdev, u8 page)
+ 
+ static int hci_read_local_ext_features_1_sync(struct hci_dev *hdev)
+ {
++	if (hci_test_quirk(hdev, HCI_QUIRK_BROKEN_LOCAL_EXT_FEATURES))
++			return 0;
++
+ 	return hci_read_local_ext_features_sync(hdev, 0x01);
+ }
+