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[PATCH v2] Bluetooth: btusb: Reject autosuspend if discovery is active

Linmao Li posted 1 patch 1 month ago
There is a newer version of this series
drivers/bluetooth/btusb.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
[PATCH v2] Bluetooth: btusb: Reject autosuspend if discovery is active
Posted by Linmao Li 1 month ago 
If USB autosuspend occurs while discovery is active, the ongoing
HCI operation may not complete successfully. On some devices, this
can leave discovery.state stuck in DISCOVERY_FINDING.

Signed-off-by: Linmao Li <lilinmao@kylinos.cn>
---
 drivers/bluetooth/btusb.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index ded09e94d296..565e276be3b2 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -4469,10 +4469,11 @@ static int btusb_suspend(struct usb_interface *intf, pm_message_t message)
 
 	BT_DBG("intf %p", intf);
 
-	/* Don't auto-suspend if there are connections; external suspend calls
-	 * shall never fail.
+	/* Don't auto-suspend if there are connections or discovery in
+	 * progress; external suspend calls shall never fail.
 	 */
-	if (PMSG_IS_AUTO(message) && hci_conn_count(data->hdev))
+	if (PMSG_IS_AUTO(message) &&
+	    (hci_conn_count(data->hdev) || hci_discovery_active(data->hdev)))
 		return -EBUSY;
 
 	if (data->suspend_count++)
-- 
2.25.1
Re: [PATCH v2] Bluetooth: btusb: Reject autosuspend if discovery is active
Posted by Linmao Li 1 month ago 
在 2026/1/8 10:06, Linmao Li 写道:

> If USB autosuspend occurs while discovery is active, the ongoing
> HCI operation may not complete successfully. On some devices, this
> can leave discovery.state stuck in DISCOVERY_FINDING.
>
> Signed-off-by: Linmao Li <lilinmao@kylinos.cn>
> ---
>   drivers/bluetooth/btusb.c | 7 ++++---
>   1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
> index ded09e94d296..565e276be3b2 100644
> --- a/drivers/bluetooth/btusb.c
> +++ b/drivers/bluetooth/btusb.c
> @@ -4469,10 +4469,11 @@ static int btusb_suspend(struct usb_interface *intf, pm_message_t message)
>   
>   	BT_DBG("intf %p", intf);
>   
> -	/* Don't auto-suspend if there are connections; external suspend calls
> -	 * shall never fail.
> +	/* Don't auto-suspend if there are connections or discovery in
> +	 * progress; external suspend calls shall never fail.
>   	 */
> -	if (PMSG_IS_AUTO(message) && hci_conn_count(data->hdev))
> +	if (PMSG_IS_AUTO(message) &&
> +	    (hci_conn_count(data->hdev) || hci_discovery_active(data->hdev)))
>   		return -EBUSY;
>   
>   	if (data->suspend_count++)
Hi Luiz,

I found that hci_discovery_active() is not exported, so btusb as a
module cannot use it:

ERROR: modpost: "hci_discovery_active" [drivers/bluetooth/btusb.ko] 
undefined!

Should I send a separate patch to export hci_discovery_active(), or
revert to v1 using test_bit(HCI_INQUIRY) and hci_dev_test_flag(HCI_LE_SCAN)?

Best regards,
Linmao
Re: [PATCH v2] Bluetooth: btusb: Reject autosuspend if discovery is active
Posted by Luiz Augusto von Dentz 1 month ago 
Hi Linmao,

On Wed, Jan 7, 2026 at 9:53 PM Linmao Li <lilinmao@kylinos.cn> wrote:
>
> 在 2026/1/8 10:06, Linmao Li 写道:
>
> > If USB autosuspend occurs while discovery is active, the ongoing
> > HCI operation may not complete successfully. On some devices, this
> > can leave discovery.state stuck in DISCOVERY_FINDING.
> >
> > Signed-off-by: Linmao Li <lilinmao@kylinos.cn>
> > ---
> >   drivers/bluetooth/btusb.c | 7 ++++---
> >   1 file changed, 4 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
> > index ded09e94d296..565e276be3b2 100644
> > --- a/drivers/bluetooth/btusb.c
> > +++ b/drivers/bluetooth/btusb.c
> > @@ -4469,10 +4469,11 @@ static int btusb_suspend(struct usb_interface *intf, pm_message_t message)
> >
> >       BT_DBG("intf %p", intf);
> >
> > -     /* Don't auto-suspend if there are connections; external suspend calls
> > -      * shall never fail.
> > +     /* Don't auto-suspend if there are connections or discovery in
> > +      * progress; external suspend calls shall never fail.
> >        */
> > -     if (PMSG_IS_AUTO(message) && hci_conn_count(data->hdev))
> > +     if (PMSG_IS_AUTO(message) &&
> > +         (hci_conn_count(data->hdev) || hci_discovery_active(data->hdev)))
> >               return -EBUSY;
> >
> >       if (data->suspend_count++)
> Hi Luiz,
>
> I found that hci_discovery_active() is not exported, so btusb as a
> module cannot use it:
>
> ERROR: modpost: "hci_discovery_active" [drivers/bluetooth/btusb.ko]
> undefined!
>
> Should I send a separate patch to export hci_discovery_active(), or
> revert to v1 using test_bit(HCI_INQUIRY) and hci_dev_test_flag(HCI_LE_SCAN)?

Just add a patch exporting it.

-- 
Luiz Augusto von Dentz
[PATCH v3 0/2] Bluetooth: btusb: Reject autosuspend if discovery is active
Posted by Linmao Li 1 month ago 
This series fixes an issue where USB autosuspend during discovery
can leave the HCI state machine in an inconsistent state.

v3:
  - Export hci_discovery_active() in patch 1
  - Use hci_discovery_active() in btusb in patch 2

v2:
  - Use hci_discovery_active() instead of testing individual bits
    (Luiz Augusto von Dentz)

Linmao Li (2):
  Bluetooth: hci_core: Export hci_discovery_active
  Bluetooth: btusb: Reject autosuspend if discovery is active

 drivers/bluetooth/btusb.c | 7 ++++---
 net/bluetooth/hci_core.c  | 1 +
 2 files changed, 5 insertions(+), 3 deletions(-)

-- 
2.25.1
[PATCH v3 1/2] Bluetooth: hci_core: Export hci_discovery_active
Posted by Linmao Li 1 month ago 
Export hci_discovery_active() so it can be used by bluetooth
drivers built as modules.

Signed-off-by: Linmao Li <lilinmao@kylinos.cn>
---
 net/bluetooth/hci_core.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 8ccec73dce45..b069607b145b 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -117,6 +117,7 @@ bool hci_discovery_active(struct hci_dev *hdev)
 		return false;
 	}
 }
+EXPORT_SYMBOL(hci_discovery_active);
 
 void hci_discovery_set_state(struct hci_dev *hdev, int state)
 {
-- 
2.25.1
[PATCH v3 2/2] Bluetooth: btusb: Reject autosuspend if discovery is active
Posted by Linmao Li 1 month ago 
If USB autosuspend occurs while discovery is active, the ongoing
HCI operation may not complete successfully. On some devices, this
can leave discovery.state stuck in DISCOVERY_FINDING.

Signed-off-by: Linmao Li <lilinmao@kylinos.cn>
---
 drivers/bluetooth/btusb.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index ded09e94d296..565e276be3b2 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -4469,10 +4469,11 @@ static int btusb_suspend(struct usb_interface *intf, pm_message_t message)
 
 	BT_DBG("intf %p", intf);
 
-	/* Don't auto-suspend if there are connections; external suspend calls
-	 * shall never fail.
+	/* Don't auto-suspend if there are connections or discovery in
+	 * progress; external suspend calls shall never fail.
 	 */
-	if (PMSG_IS_AUTO(message) && hci_conn_count(data->hdev))
+	if (PMSG_IS_AUTO(message) &&
+	    (hci_conn_count(data->hdev) || hci_discovery_active(data->hdev)))
 		return -EBUSY;
 
 	if (data->suspend_count++)
-- 
2.25.1

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