2020-06-02 01:44:20

by Manish Mandlik

[permalink] [raw]
Subject: [PATCH] Bluetooth: Check scan state before disabling during suspend

Check current scan state by checking HCI_LE_SCAN flag and send scan
disable command only if scan is already enabled.

Signed-off-by: Manish Mandlik <[email protected]>
---

net/bluetooth/hci_request.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/net/bluetooth/hci_request.c b/net/bluetooth/hci_request.c
index 1fc55685da62d..1acf5b8e0910c 100644
--- a/net/bluetooth/hci_request.c
+++ b/net/bluetooth/hci_request.c
@@ -998,8 +998,9 @@ static void hci_req_set_event_filter(struct hci_request *req)

static void hci_req_config_le_suspend_scan(struct hci_request *req)
{
- /* Can't change params without disabling first */
- hci_req_add_le_scan_disable(req);
+ /* Before changing params disable scan if enabled */
+ if (hci_dev_test_flag(req->hdev, HCI_LE_SCAN))
+ hci_req_add_le_scan_disable(req);

/* Configure params and enable scanning */
hci_req_add_le_passive_scan(req);
@@ -1065,8 +1066,9 @@ void hci_req_prepare_suspend(struct hci_dev *hdev, enum suspended_state next)
page_scan = SCAN_DISABLED;
hci_req_add(&req, HCI_OP_WRITE_SCAN_ENABLE, 1, &page_scan);

- /* Disable LE passive scan */
- hci_req_add_le_scan_disable(&req);
+ /* Disable LE passive scan if enabled */
+ if (hci_dev_test_flag(hdev, HCI_LE_SCAN))
+ hci_req_add_le_scan_disable(&req);

/* Mark task needing completion */
set_bit(SUSPEND_SCAN_DISABLE, hdev->suspend_tasks);
--
2.27.0.rc2.251.g90737beb825-goog


2020-06-02 01:49:40

by Abhishek Pandit-Subedi

[permalink] [raw]
Subject: Re: [PATCH] Bluetooth: Check scan state before disabling during suspend

Hey linux-bluetooth,

We found this bug when reverting some Chromium maintained patches in
our repository that was conditionally dropping LE scan enable commands
if it wasn't toggling between true/false. On some Intel controllers,
disabling LE scan when it's already disabled resulted in a "Command
Disallowed" and this was causing suspend to fail.

On Mon, Jun 1, 2020 at 6:43 PM Manish Mandlik <[email protected]> wrote:
>
> Check current scan state by checking HCI_LE_SCAN flag and send scan
> disable command only if scan is already enabled.
>
> Signed-off-by: Manish Mandlik <[email protected]>
> ---
>
> net/bluetooth/hci_request.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/net/bluetooth/hci_request.c b/net/bluetooth/hci_request.c
> index 1fc55685da62d..1acf5b8e0910c 100644
> --- a/net/bluetooth/hci_request.c
> +++ b/net/bluetooth/hci_request.c
> @@ -998,8 +998,9 @@ static void hci_req_set_event_filter(struct hci_request *req)
>
> static void hci_req_config_le_suspend_scan(struct hci_request *req)
> {
> - /* Can't change params without disabling first */
> - hci_req_add_le_scan_disable(req);
> + /* Before changing params disable scan if enabled */
> + if (hci_dev_test_flag(req->hdev, HCI_LE_SCAN))
> + hci_req_add_le_scan_disable(req);
>
> /* Configure params and enable scanning */
> hci_req_add_le_passive_scan(req);
> @@ -1065,8 +1066,9 @@ void hci_req_prepare_suspend(struct hci_dev *hdev, enum suspended_state next)
> page_scan = SCAN_DISABLED;
> hci_req_add(&req, HCI_OP_WRITE_SCAN_ENABLE, 1, &page_scan);
>
> - /* Disable LE passive scan */
> - hci_req_add_le_scan_disable(&req);
> + /* Disable LE passive scan if enabled */
> + if (hci_dev_test_flag(hdev, HCI_LE_SCAN))
> + hci_req_add_le_scan_disable(&req);
>
> /* Mark task needing completion */
> set_bit(SUSPEND_SCAN_DISABLE, hdev->suspend_tasks);
> --
> 2.27.0.rc2.251.g90737beb825-goog
>

Reviewed-by: Abhishek Pandit-Subedi <[email protected]>

2020-06-02 12:29:08

by Alain Michaud

[permalink] [raw]
Subject: Re: [PATCH] Bluetooth: Check scan state before disabling during suspend

On Mon, Jun 1, 2020 at 9:49 PM Abhishek Pandit-Subedi
<[email protected]> wrote:
>
> Hey linux-bluetooth,
>
> We found this bug when reverting some Chromium maintained patches in
> our repository that was conditionally dropping LE scan enable commands
> if it wasn't toggling between true/false. On some Intel controllers,
> disabling LE scan when it's already disabled resulted in a "Command
> Disallowed" and this was causing suspend to fail.
>
> On Mon, Jun 1, 2020 at 6:43 PM Manish Mandlik <[email protected]> wrote:
> >
> > Check current scan state by checking HCI_LE_SCAN flag and send scan
> > disable command only if scan is already enabled.
> >
> > Signed-off-by: Manish Mandlik <[email protected]>
> > ---
> >
> > net/bluetooth/hci_request.c | 10 ++++++----
> > 1 file changed, 6 insertions(+), 4 deletions(-)
> >
> > diff --git a/net/bluetooth/hci_request.c b/net/bluetooth/hci_request.c
> > index 1fc55685da62d..1acf5b8e0910c 100644
> > --- a/net/bluetooth/hci_request.c
> > +++ b/net/bluetooth/hci_request.c
> > @@ -998,8 +998,9 @@ static void hci_req_set_event_filter(struct hci_request *req)
> >
> > static void hci_req_config_le_suspend_scan(struct hci_request *req)
> > {
> > - /* Can't change params without disabling first */
> > - hci_req_add_le_scan_disable(req);
> > + /* Before changing params disable scan if enabled */
> > + if (hci_dev_test_flag(req->hdev, HCI_LE_SCAN))
> > + hci_req_add_le_scan_disable(req);
> >
> > /* Configure params and enable scanning */
> > hci_req_add_le_passive_scan(req);
> > @@ -1065,8 +1066,9 @@ void hci_req_prepare_suspend(struct hci_dev *hdev, enum suspended_state next)
> > page_scan = SCAN_DISABLED;
> > hci_req_add(&req, HCI_OP_WRITE_SCAN_ENABLE, 1, &page_scan);
> >
> > - /* Disable LE passive scan */
> > - hci_req_add_le_scan_disable(&req);
> > + /* Disable LE passive scan if enabled */
> > + if (hci_dev_test_flag(hdev, HCI_LE_SCAN))
> > + hci_req_add_le_scan_disable(&req);
> >
> > /* Mark task needing completion */
> > set_bit(SUSPEND_SCAN_DISABLE, hdev->suspend_tasks);
> > --
> > 2.27.0.rc2.251.g90737beb825-goog
> >
>
> Reviewed-by: Abhishek Pandit-Subedi <[email protected]>
Reviewed-by: Alain Michaud <[email protected]>
>
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2020-06-03 17:53:18

by Marcel Holtmann

[permalink] [raw]
Subject: Re: [PATCH] Bluetooth: Check scan state before disabling during suspend

Hi Manish,

> Check current scan state by checking HCI_LE_SCAN flag and send scan
> disable command only if scan is already enabled.
>
> Signed-off-by: Manish Mandlik <[email protected]>
> ---
>
> net/bluetooth/hci_request.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)

patch has been applied to bluetooth-next tree.

Regards

Marcel