[PATCH v2] Bluetooth: qca: Disable SoC debug logging for WCN3990

[Hex Lindqvist <hex@freenixos.com>]

Unless the host turns it off, the WCN3990 firmware sends debug logs to
the host as ACL packets on handle 0x2EDC. hci_qca passes them on as
diagnostic packets, which the core copies to the monitor socket and then
frees, so nothing appears in the kernel log. btmon shows them as:

  = Vendor Diagnostic (len 492)                      [hci0] 0.761331
          dc 2e e8 01 e4 01 03 00 0a ff 10 04 01 00 55 53
  = Vendor Diagnostic (len 481)                     [hci0] 11.334015
          dc 2e dd 01 d9 01 04 00 0a ff 10 04 01 00 51 d3

On a OnePlus 6T (SoC version 0x40010214, ROM version 0x0201) that is a
packet of about 490 bytes every seven to ten seconds, for as long as the
controller is up.

The driver already turns this logging off after the firmware download
for WCN3950 and WCN3991. Do the same for WCN3990.

Tested on a OnePlus 6T with two builds of crbtfw21.tlv. With the one
from the OnePlus firmware, BTFM.CHE.2.1.4.c2-00002-QCACHROMZ-2.184841.1,
no diagnostic packets arrive any more. The one from linux-firmware,
BTFM.CHE.2.1.3.c7-00024-QCACHROM-1, also accepts the command.

An AI assistant helped find and test this change and drafted this
message.

Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Hex Lindqvist <hex@freenixos.com>
---
Changes in v2:
- Say that nothing is logged, add a btmon excerpt and name the two
  crbtfw21.tlv builds (Paul)
- Add Reviewed-by tags; no code change

v1: https://lore.kernel.org/r/20261105201952.1556185-1-hex@freenixos.com

 drivers/bluetooth/btqca.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/bluetooth/btqca.c b/drivers/bluetooth/btqca.c
index 60735b70d89a..1db2cc626def 100644
--- a/drivers/bluetooth/btqca.c
+++ b/drivers/bluetooth/btqca.c
@@ -944,6 +944,7 @@ int qca_uart_setup(struct hci_dev *hdev, uint8_t baudrate,
 	case QCA_QCA2066:
 	case QCA_QCA6390:
 	case QCA_WCN3950:
+	case QCA_WCN3990:
 	case QCA_WCN3991:
 	case QCA_WCN6750:
 	case QCA_WCN6855:

base-commit: ebdfe8561b5496b7eafedccd13a000a7261bc52b
-- 
2.56.0