Re: [PATCH] Bluetooth: btusb: limit RTL8761B BROKEN_EXT_SCAN quirk to 0bda:a728

On 8/24/26 07:32, Junjie Cao wrote:
> Commit 5ead2063611a ("Bluetooth: btrtl: fix RTL8761B/BU broken LE
> extended scan") set HCI_QUIRK_BROKEN_EXT_SCAN for every CHIP_ID_8761B
> device to cure repeated 0x2042 failures on an 0bda:a728 dongle. The
> brokenness is per-dongle, not per-chip: on a TP-Link UB500 (2357:0604,
> RTL8761BU, fw 0xdfc6d922) extended scan works, and the legacy scan
> path the quirk forces is what is broken -- LE Set Scan Enable (0x200c)
> times out with -110 about 30 s after firmware load, btusb resets the
> device, and the adapter re-enumerates in an endless loop (382 firmware
> reloads in one boot). 7.1.8, which predates the stable backport, runs
> clean on this unit; 7.1.9 loops.
> 
> Move the quirk from btrtl's chip-wide switch to a btusb device-table
> flag on the USB id the original fix was verified against. Other 8761B
> dongles return to their earlier long-standing behaviour.
> > Link: https://bugzilla.redhat.com/show_bug.cgi?id=2521504
> Fixes: 5ead2063611a ("Bluetooth: btrtl: fix RTL8761B/BU broken LE extended scan")

Thx. Just to make sure everyone is aware of it: Kamil (now CCed)
reported problems due to the commit yesterday and provided patches, too:
https://lore.kernel.org/all/[email protected]/

I suggested that a quick revert might be the best approach for now,
which Kamil submitted:
https://lore.kernel.org/all/[email protected]/

No comment yet from the BT folks yet.

Ciao, Thorsten

> Cc: [email protected]
> Signed-off-by: Junjie Cao <[email protected]>
> ---
> #regzbot introduced: 5ead2063611a
> #regzbot link: https://bugzilla.redhat.com/show_bug.cgi?id=2521504
> 
>  drivers/bluetooth/btrtl.c | 13 -------------
>  drivers/bluetooth/btusb.c |  8 ++++++++
>  2 files changed, 8 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/bluetooth/btrtl.c b/drivers/bluetooth/btrtl.c
> index 7f54d2d2d13a..03fa9409e3ee 100644
> --- a/drivers/bluetooth/btrtl.c
> +++ b/drivers/bluetooth/btrtl.c
> @@ -1343,19 +1343,6 @@ void btrtl_set_quirks(struct hci_dev *hdev, struct btrtl_device_info *btrtl_dev)
>  	if (!btrtl_dev->ic_info)
>  		return;
>  
> -	switch (btrtl_dev->project_id) {
> -	case CHIP_ID_8761B:
> -		/* RTL8761B/BU reports HCI version 5.1 but does not support
> -		 * the LE Extended Scan commands (Opcode 0x2042), causing
> -		 * repeated -EBUSY failures when BlueZ attempts extended
> -		 * scanning while a connection is active.
> -		 */
> -		hci_set_quirk(hdev, HCI_QUIRK_BROKEN_EXT_SCAN);
> -		break;
> -	default:
> -		break;
> -	}
> -
>  	switch (btrtl_dev->ic_info->lmp_subver) {
>  	case RTL_ROM_LMP_8703B:
>  		/* 8723CS reports two pages for local ext features,
> diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
> index 2bae85b0016c..84614e60d142 100644
> --- a/drivers/bluetooth/btusb.c
> +++ b/drivers/bluetooth/btusb.c
> @@ -67,6 +67,7 @@ static struct usb_driver btusb_driver;
>  #define BTUSB_INTEL_NO_WBS_SUPPORT	BIT(26)
>  #define BTUSB_ACTIONS_SEMI		BIT(27)
>  #define BTUSB_BARROT			BIT(28)
> +#define BTUSB_BROKEN_EXT_SCAN		BIT(29)
>  
>  static const struct usb_device_id btusb_table[] = {
>  	/* Generic Bluetooth USB device */
> @@ -619,6 +620,10 @@ static const struct usb_device_id quirks_table[] = {
>  	{ USB_DEVICE(0x0489, 0xe130), .driver_info = BTUSB_REALTEK |
>  						     BTUSB_WIDEBAND_SPEECH },
>  
> +	/* Realtek 8761BU Bluetooth devices */
> +	{ USB_DEVICE(0x0bda, 0xa728), .driver_info = BTUSB_REALTEK |
> +						     BTUSB_BROKEN_EXT_SCAN },
> +
>  	/* Realtek Bluetooth devices */
>  	{ USB_VENDOR_AND_INTERFACE_INFO(0x0bda, 0xe0, 0x01, 0x01),
>  	  .driver_info = BTUSB_REALTEK },
> @@ -4403,6 +4408,9 @@ static int btusb_probe(struct usb_interface *intf,
>  	if (id->driver_info & BTUSB_INVALID_LE_STATES)
>  		hci_set_quirk(hdev, HCI_QUIRK_BROKEN_LE_STATES);
>  
> +	if (id->driver_info & BTUSB_BROKEN_EXT_SCAN)
> +		hci_set_quirk(hdev, HCI_QUIRK_BROKEN_EXT_SCAN);
> +
>  	if (id->driver_info & BTUSB_DIGIANSWER) {
>  		data->cmdreq_type = USB_TYPE_VENDOR;
>  		hci_set_quirk(hdev, HCI_QUIRK_RESET_ON_CLOSE);