[ARCHIVED] Fix for CSR Dongle 0a12:0001 ID 0a12:0001 Cambridge Silicon Radio, Ltd Bluetooth Dongle (HCI mode)

archived.md

This gist is currenctly archived.

Please refer to previous revisions if you know what to do.

The patch proposed was merged into kernel in 5.8 release, but no longer working as of linux 5.11

Yes, that was also my biggest take home message
https://bugzilla.kernel.org/show_bug.cgi?id=60824#c167

Found this patch, but it's for a newer kernel:

--- a/net/bluetooth/hci_sync.c	2025-07-28 20:25:38.718355109 -0300
+++ b/net/bluetooth/hci_sync.c	2025-07-28 20:30:02.004160831 -0300
@@ -3960,8 +3960,6 @@
 	HCI_INIT(hci_write_inquiry_mode_sync),
 	/* 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_OP_WRITE_AUTH_ENABLE */
 	HCI_INIT(hci_write_auth_enable_sync),
 	{}
@@ -4252,8 +4250,6 @@
 	HCI_INIT(hci_read_def_err_data_reporting_sync),
 	/* HCI_OP_READ_PAGE_SCAN_TYPE */
 	HCI_INIT(hci_read_page_scan_type_sync),
-	/* HCI_OP_READ_LOCAL_EXT_FEATURES */
-	HCI_INIT(hci_read_local_ext_features_all_sync),
 	{}
 };

There's no net/bluetooth/hci_sync.c in 5.15.

I made additional patch for 5.15, now all my adapters work more or less. Even with the other IDs, 33fa:0010, 33fa:0012 from UGREEN.

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 7ed5d6e..0f16d88 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -482,6 +482,7 @@ static int hci_init2_req(struct hci_request *req, unsigned long opt)
 	if (lmp_inq_tx_pwr_capable(hdev))
 		hci_req_add(req, HCI_OP_READ_INQ_RSP_TX_POWER, 0, NULL);
 
+	if (0) // FIX
 	if (lmp_ext_feat_capable(hdev)) {
 		struct hci_cp_read_local_ext_features cp;
 
@@ -797,6 +798,7 @@ static int hci_init3_req(struct hci_request *req, unsigned long opt)
 	}
 
 	/* Read features beyond page 1 if available */
+	if (0) // FIX
 	for (p = 2; p < HCI_MAX_PAGES && p <= hdev->max_page; p++) {
 		struct hci_cp_read_local_ext_features cp;