[PATCH 0/3]

[PATCH 0/3]

[Matthias Kaehlcke]

This series includes a fix for a possible race in qca_suspend() and
some minor refactoring of the same function.


Matthias Kaehlcke (3):
  Bluetooth: hci_qca: Only remove TX clock vote after TX is completed
  Bluetooth: hci_qca: Skip serdev wait when no transfer is pending
  Bluetooth: hci_qca: Refactor error handling in qca_suspend()

 drivers/bluetooth/hci_qca.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

-- 
2.27.0.278.ge193c7cf3a9-goog

[PATCH 1/3] Bluetooth: hci_qca: Only remove TX clock vote after TX is completed

[Matthias Kaehlcke]

qca_suspend() removes the vote for the UART TX clock after
writing an IBS sleep request to the serial buffer. This is
not a good idea since there is no guarantee that the request
has been sent at this point. Instead remove the vote after
successfully entering IBS sleep. This also fixes the issue
of the vote being removed in case of an aborted suspend due
to a failure of entering IBS sleep.

Fixes: 41d5b25fed0a0 ("Bluetooth: hci_qca: add PM support")
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
---

 drivers/bluetooth/hci_qca.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
index ece9f91cc3deb..b1d82d32892e9 100644
--- a/drivers/bluetooth/hci_qca.c
+++ b/drivers/bluetooth/hci_qca.c
@@ -2083,8 +2083,6 @@ static int __maybe_unused qca_suspend(struct device *dev)
 
 		qca->tx_ibs_state = HCI_IBS_TX_ASLEEP;
 		qca->ibs_sent_slps++;
-
-		qca_wq_serial_tx_clock_vote_off(&qca->ws_tx_vote_off);
 		break;
 
 	case HCI_IBS_TX_ASLEEP:
@@ -2112,8 +2110,10 @@ static int __maybe_unused qca_suspend(struct device *dev)
 			qca->rx_ibs_state == HCI_IBS_RX_ASLEEP,
 			msecs_to_jiffies(IBS_BTSOC_TX_IDLE_TIMEOUT_MS));
 
-	if (ret > 0)
+	if (ret > 0) {
+		qca_wq_serial_tx_clock_vote_off(&qca->ws_tx_vote_off);
 		return 0;
+	}
 
 	if (ret == 0)
 		ret = -ETIMEDOUT;
-- 
2.27.0.278.ge193c7cf3a9-goog

[PATCH 2/3] Bluetooth: hci_qca: Skip serdev wait when no transfer is pending

[Matthias Kaehlcke]

qca_suspend() calls serdev_device_wait_until_sent() regardless of
whether a transfer is pending. While it does no active harm since
the function should return immediately it makes the code more
confusing. Add a flag to track whether a transfer is pending and
only call serdev_device_wait_until_sent() is needed.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
---

 drivers/bluetooth/hci_qca.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
index b1d82d32892e9..90ffd8ca1fb0d 100644
--- a/drivers/bluetooth/hci_qca.c
+++ b/drivers/bluetooth/hci_qca.c
@@ -2050,6 +2050,7 @@ static int __maybe_unused qca_suspend(struct device *dev)
 	struct hci_uart *hu = &qcadev->serdev_hu;
 	struct qca_data *qca = hu->priv;
 	unsigned long flags;
+	bool tx_pending = false;
 	int ret = 0;
 	u8 cmd;
 
@@ -2083,6 +2084,7 @@ static int __maybe_unused qca_suspend(struct device *dev)
 
 		qca->tx_ibs_state = HCI_IBS_TX_ASLEEP;
 		qca->ibs_sent_slps++;
+		tx_pending = true;
 		break;
 
 	case HCI_IBS_TX_ASLEEP:
@@ -2099,8 +2101,10 @@ static int __maybe_unused qca_suspend(struct device *dev)
 	if (ret < 0)
 		goto error;
 
-	serdev_device_wait_until_sent(hu->serdev,
-				      msecs_to_jiffies(CMD_TRANS_TIMEOUT_MS));
+	if (tx_pending) {
+		serdev_device_wait_until_sent(hu->serdev,
+					      msecs_to_jiffies(CMD_TRANS_TIMEOUT_MS));
+	}
 
 	/* Wait for HCI_IBS_SLEEP_IND sent by device to indicate its Tx is going
 	 * to sleep, so that the packet does not wake the system later.
-- 
2.27.0.278.ge193c7cf3a9-goog

[PATCH 3/3] Bluetooth: hci_qca: Refactor error handling in qca_suspend()

[Matthias Kaehlcke]

If waiting for IBS sleep times out jump to the error handler, this is
easier to read than multiple 'if' branches and a fall through to the
error handler.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
---

 drivers/bluetooth/hci_qca.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
index 90ffd8ca1fb0d..cf76f128e9834 100644
--- a/drivers/bluetooth/hci_qca.c
+++ b/drivers/bluetooth/hci_qca.c
@@ -2109,18 +2109,16 @@ static int __maybe_unused qca_suspend(struct device *dev)
 	/* Wait for HCI_IBS_SLEEP_IND sent by device to indicate its Tx is going
 	 * to sleep, so that the packet does not wake the system later.
 	 */
-
 	ret = wait_event_interruptible_timeout(qca->suspend_wait_q,
 			qca->rx_ibs_state == HCI_IBS_RX_ASLEEP,
 			msecs_to_jiffies(IBS_BTSOC_TX_IDLE_TIMEOUT_MS));
-
-	if (ret > 0) {
-		qca_wq_serial_tx_clock_vote_off(&qca->ws_tx_vote_off);
-		return 0;
+	if (ret == 0) {
+		ret = -ETIMEDOUT;
+		goto error;
 	}
 
-	if (ret == 0)
-		ret = -ETIMEDOUT;
+	qca_wq_serial_tx_clock_vote_off(&qca->ws_tx_vote_off);
+	return 0;
 
 error:
 	clear_bit(QCA_SUSPENDING, &qca->flags);
-- 
2.27.0.278.ge193c7cf3a9-goog

Re: [PATCH 1/3] Bluetooth: hci_qca: Only remove TX clock vote after TX is completed

[Abhishek Pandit-Subedi]

Hi,

On Fri, Jun 5, 2020 at 11:46 AM Matthias Kaehlcke <mka@chromium.org> wrote:
>
> qca_suspend() removes the vote for the UART TX clock after
> writing an IBS sleep request to the serial buffer. This is
> not a good idea since there is no guarantee that the request
> has been sent at this point. Instead remove the vote after
> successfully entering IBS sleep. This also fixes the issue
> of the vote being removed in case of an aborted suspend due
> to a failure of entering IBS sleep.
>
> Fixes: 41d5b25fed0a0 ("Bluetooth: hci_qca: add PM support")
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> ---
>
>  drivers/bluetooth/hci_qca.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index ece9f91cc3deb..b1d82d32892e9 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -2083,8 +2083,6 @@ static int __maybe_unused qca_suspend(struct device *dev)
>
>                 qca->tx_ibs_state = HCI_IBS_TX_ASLEEP;
>                 qca->ibs_sent_slps++;
> -
> -               qca_wq_serial_tx_clock_vote_off(&qca->ws_tx_vote_off);
>                 break;
>
>         case HCI_IBS_TX_ASLEEP:
> @@ -2112,8 +2110,10 @@ static int __maybe_unused qca_suspend(struct device *dev)
>                         qca->rx_ibs_state == HCI_IBS_RX_ASLEEP,
>                         msecs_to_jiffies(IBS_BTSOC_TX_IDLE_TIMEOUT_MS));
>
> -       if (ret > 0)
> +       if (ret > 0) {
> +               qca_wq_serial_tx_clock_vote_off(&qca->ws_tx_vote_off);
>                 return 0;
> +       }
>
>         if (ret == 0)
>                 ret = -ETIMEDOUT;
> --
> 2.27.0.278.ge193c7cf3a9-goog
>

I checked the order of calls and it looks correct per commit message.

Reviewed-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>

Re: [PATCH 2/3] Bluetooth: hci_qca: Skip serdev wait when no transfer is pending

[Abhishek Pandit-Subedi]

Reviewed-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>

On Fri, Jun 5, 2020 at 11:46 AM Matthias Kaehlcke <mka@chromium.org> wrote:
>
> qca_suspend() calls serdev_device_wait_until_sent() regardless of
> whether a transfer is pending. While it does no active harm since
> the function should return immediately it makes the code more
> confusing. Add a flag to track whether a transfer is pending and
> only call serdev_device_wait_until_sent() is needed.
>
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> ---
>
>  drivers/bluetooth/hci_qca.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index b1d82d32892e9..90ffd8ca1fb0d 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -2050,6 +2050,7 @@ static int __maybe_unused qca_suspend(struct device *dev)
>         struct hci_uart *hu = &qcadev->serdev_hu;
>         struct qca_data *qca = hu->priv;
>         unsigned long flags;
> +       bool tx_pending = false;
>         int ret = 0;
>         u8 cmd;
>
> @@ -2083,6 +2084,7 @@ static int __maybe_unused qca_suspend(struct device *dev)
>
>                 qca->tx_ibs_state = HCI_IBS_TX_ASLEEP;
>                 qca->ibs_sent_slps++;
> +               tx_pending = true;
>                 break;
>
>         case HCI_IBS_TX_ASLEEP:
> @@ -2099,8 +2101,10 @@ static int __maybe_unused qca_suspend(struct device *dev)
>         if (ret < 0)
>                 goto error;
>
> -       serdev_device_wait_until_sent(hu->serdev,
> -                                     msecs_to_jiffies(CMD_TRANS_TIMEOUT_MS));
> +       if (tx_pending) {
> +               serdev_device_wait_until_sent(hu->serdev,
> +                                             msecs_to_jiffies(CMD_TRANS_TIMEOUT_MS));
> +       }
>
>         /* Wait for HCI_IBS_SLEEP_IND sent by device to indicate its Tx is going
>          * to sleep, so that the packet does not wake the system later.
> --
> 2.27.0.278.ge193c7cf3a9-goog
>

Re: [PATCH 3/3] Bluetooth: hci_qca: Refactor error handling in qca_suspend()

[Abhishek Pandit-Subedi]

Reviewed-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>

On Fri, Jun 5, 2020 at 11:46 AM Matthias Kaehlcke <mka@chromium.org> wrote:
>
> If waiting for IBS sleep times out jump to the error handler, this is
> easier to read than multiple 'if' branches and a fall through to the
> error handler.
>
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> ---
>
>  drivers/bluetooth/hci_qca.c | 12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index 90ffd8ca1fb0d..cf76f128e9834 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -2109,18 +2109,16 @@ static int __maybe_unused qca_suspend(struct device *dev)
>         /* Wait for HCI_IBS_SLEEP_IND sent by device to indicate its Tx is going
>          * to sleep, so that the packet does not wake the system later.
>          */
> -
>         ret = wait_event_interruptible_timeout(qca->suspend_wait_q,
>                         qca->rx_ibs_state == HCI_IBS_RX_ASLEEP,
>                         msecs_to_jiffies(IBS_BTSOC_TX_IDLE_TIMEOUT_MS));
> -
> -       if (ret > 0) {
> -               qca_wq_serial_tx_clock_vote_off(&qca->ws_tx_vote_off);
> -               return 0;
> +       if (ret == 0) {
> +               ret = -ETIMEDOUT;
> +               goto error;
>         }
>
> -       if (ret == 0)
> -               ret = -ETIMEDOUT;
> +       qca_wq_serial_tx_clock_vote_off(&qca->ws_tx_vote_off);
> +       return 0;
>
>  error:
>         clear_bit(QCA_SUSPENDING, &qca->flags);
> --
> 2.27.0.278.ge193c7cf3a9-goog
>

Re: [PATCH 1/3] Bluetooth: hci_qca: Only remove TX clock vote after TX is completed

[bgodavar]

Hi Matthias,

On 2020-06-06 00:16, Matthias Kaehlcke wrote:
> qca_suspend() removes the vote for the UART TX clock after
> writing an IBS sleep request to the serial buffer. This is
> not a good idea since there is no guarantee that the request
> has been sent at this point. Instead remove the vote after
> successfully entering IBS sleep. This also fixes the issue
> of the vote being removed in case of an aborted suspend due
> to a failure of entering IBS sleep.
> 
> Fixes: 41d5b25fed0a0 ("Bluetooth: hci_qca: add PM support")
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> ---
> 
>  drivers/bluetooth/hci_qca.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index ece9f91cc3deb..b1d82d32892e9 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -2083,8 +2083,6 @@ static int __maybe_unused qca_suspend(struct 
> device *dev)
> 
>  		qca->tx_ibs_state = HCI_IBS_TX_ASLEEP;
>  		qca->ibs_sent_slps++;
> -
> -		qca_wq_serial_tx_clock_vote_off(&qca->ws_tx_vote_off);
>  		break;
> 
>  	case HCI_IBS_TX_ASLEEP:
> @@ -2112,8 +2110,10 @@ static int __maybe_unused qca_suspend(struct 
> device *dev)
>  			qca->rx_ibs_state == HCI_IBS_RX_ASLEEP,
>  			msecs_to_jiffies(IBS_BTSOC_TX_IDLE_TIMEOUT_MS));
> 
> -	if (ret > 0)
> +	if (ret > 0) {
> +		qca_wq_serial_tx_clock_vote_off(&qca->ws_tx_vote_off);
[Bala]: qca_wq_serial_tx_clock_vote_off votes for Tx clock off, when 
both Tx clock and Rx clock voted to off.
then only actual call to clock off is called.
https://elixir.bootlin.com/linux/latest/source/drivers/bluetooth/hci_qca.c#L312
I would recommend to vote Tx clock off after sending SLEEP BYTE from 
HOST TO BT SOC.

>  		return 0;
> +	}
> 
>  	if (ret == 0)
>  		ret = -ETIMEDOUT;

Re: [PATCH 2/3] Bluetooth: hci_qca: Skip serdev wait when no transfer is pending

[bgodavar]

Hi matthias,

On 2020-06-06 00:16, Matthias Kaehlcke wrote:
> qca_suspend() calls serdev_device_wait_until_sent() regardless of
> whether a transfer is pending. While it does no active harm since
> the function should return immediately it makes the code more
> confusing. Add a flag to track whether a transfer is pending and
> only call serdev_device_wait_until_sent() is needed.
> 
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> ---
> 
>  drivers/bluetooth/hci_qca.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> index b1d82d32892e9..90ffd8ca1fb0d 100644
> --- a/drivers/bluetooth/hci_qca.c
> +++ b/drivers/bluetooth/hci_qca.c
> @@ -2050,6 +2050,7 @@ static int __maybe_unused qca_suspend(struct 
> device *dev)
>  	struct hci_uart *hu = &qcadev->serdev_hu;
>  	struct qca_data *qca = hu->priv;
>  	unsigned long flags;
> +	bool tx_pending = false;
>  	int ret = 0;
>  	u8 cmd;
> 
> @@ -2083,6 +2084,7 @@ static int __maybe_unused qca_suspend(struct 
> device *dev)
> 
>  		qca->tx_ibs_state = HCI_IBS_TX_ASLEEP;
>  		qca->ibs_sent_slps++;
> +		tx_pending = true;
>  		break;
> 
>  	case HCI_IBS_TX_ASLEEP:
> @@ -2099,8 +2101,10 @@ static int __maybe_unused qca_suspend(struct 
> device *dev)
>  	if (ret < 0)
>  		goto error;
> 
> -	serdev_device_wait_until_sent(hu->serdev,
> -				      msecs_to_jiffies(CMD_TRANS_TIMEOUT_MS));
> +	if (tx_pending) {
[Bala]: Good idea why don't we move this call to switch case under 
HCI_IBS_TX_AWAKE
https://elixir.bootlin.com/linux/latest/source/drivers/bluetooth/hci_qca.c#L1994

i.e. i would recommend below sequence

1. Send SLEEP BYTE
2. wait for some time to write SLEEP Byte on Tx line
3. call for Tx clock off qca_wq_serial_tx_clock_vote_off

> +		serdev_device_wait_until_sent(hu->serdev,
> +					      msecs_to_jiffies(CMD_TRANS_TIMEOUT_MS));
> +	}
> 
>  	/* Wait for HCI_IBS_SLEEP_IND sent by device to indicate its Tx is 
> going
>  	 * to sleep, so that the packet does not wake the system later.

Re: [PATCH 2/3] Bluetooth: hci_qca: Skip serdev wait when no transfer is pending

[Matthias Kaehlcke]

Hi Bala,

On Sat, Jun 06, 2020 at 06:27:59PM +0530, bgodavar@codeaurora.org wrote:
> Hi matthias,
> 
> On 2020-06-06 00:16, Matthias Kaehlcke wrote:
> > qca_suspend() calls serdev_device_wait_until_sent() regardless of
> > whether a transfer is pending. While it does no active harm since
> > the function should return immediately it makes the code more
> > confusing. Add a flag to track whether a transfer is pending and
> > only call serdev_device_wait_until_sent() is needed.
> > 
> > Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> > ---
> > 
> >  drivers/bluetooth/hci_qca.c | 8 ++++++--
> >  1 file changed, 6 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> > index b1d82d32892e9..90ffd8ca1fb0d 100644
> > --- a/drivers/bluetooth/hci_qca.c
> > +++ b/drivers/bluetooth/hci_qca.c
> > @@ -2050,6 +2050,7 @@ static int __maybe_unused qca_suspend(struct
> > device *dev)
> >  	struct hci_uart *hu = &qcadev->serdev_hu;
> >  	struct qca_data *qca = hu->priv;
> >  	unsigned long flags;
> > +	bool tx_pending = false;
> >  	int ret = 0;
> >  	u8 cmd;
> > 
> > @@ -2083,6 +2084,7 @@ static int __maybe_unused qca_suspend(struct
> > device *dev)
> > 
> >  		qca->tx_ibs_state = HCI_IBS_TX_ASLEEP;
> >  		qca->ibs_sent_slps++;
> > +		tx_pending = true;
> >  		break;
> > 
> >  	case HCI_IBS_TX_ASLEEP:
> > @@ -2099,8 +2101,10 @@ static int __maybe_unused qca_suspend(struct
> > device *dev)
> >  	if (ret < 0)
> >  		goto error;
> > 
> > -	serdev_device_wait_until_sent(hu->serdev,
> > -				      msecs_to_jiffies(CMD_TRANS_TIMEOUT_MS));
> > +	if (tx_pending) {
> [Bala]: Good idea why don't we move this call to switch case under
> HCI_IBS_TX_AWAKE
> https://elixir.bootlin.com/linux/latest/source/drivers/bluetooth/hci_qca.c#L1994

I agree that this would make the code easier to follow, however the
reason this wasn't done in the first place is (probably) that the
IBS spinlock is held during the switch/case block.

In principle the unlock could be done before calling _wait_until_sent(),
but then the unlock also needs to happen in the other 'case' branches.
It's not ideal, but also not necessarily worse than introducing
'tx_pending', the repeated unlocks might be preferable in terms of
readability.

> i.e. i would recommend below sequence
> 
> 1. Send SLEEP BYTE
> 2. wait for some time to write SLEEP Byte on Tx line
> 3. call for Tx clock off qca_wq_serial_tx_clock_vote_off
> 
> > +		serdev_device_wait_until_sent(hu->serdev,
> > +					      msecs_to_jiffies(CMD_TRANS_TIMEOUT_MS));
> > +	}
> > 
> >  	/* Wait for HCI_IBS_SLEEP_IND sent by device to indicate its Tx is
> > going
> >  	 * to sleep, so that the packet does not wake the system later.

Re: [PATCH 1/3] Bluetooth: hci_qca: Only remove TX clock vote after TX is completed

[Matthias Kaehlcke]

Hi Bala,

On Sat, Jun 06, 2020 at 06:23:13PM +0530, bgodavar@codeaurora.org wrote:
> Hi Matthias,
> 
> On 2020-06-06 00:16, Matthias Kaehlcke wrote:
> > qca_suspend() removes the vote for the UART TX clock after
> > writing an IBS sleep request to the serial buffer. This is
> > not a good idea since there is no guarantee that the request
> > has been sent at this point. Instead remove the vote after
> > successfully entering IBS sleep. This also fixes the issue
> > of the vote being removed in case of an aborted suspend due
> > to a failure of entering IBS sleep.
> > 
> > Fixes: 41d5b25fed0a0 ("Bluetooth: hci_qca: add PM support")
> > Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> > ---
> > 
> >  drivers/bluetooth/hci_qca.c | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/bluetooth/hci_qca.c b/drivers/bluetooth/hci_qca.c
> > index ece9f91cc3deb..b1d82d32892e9 100644
> > --- a/drivers/bluetooth/hci_qca.c
> > +++ b/drivers/bluetooth/hci_qca.c
> > @@ -2083,8 +2083,6 @@ static int __maybe_unused qca_suspend(struct
> > device *dev)
> > 
> >  		qca->tx_ibs_state = HCI_IBS_TX_ASLEEP;
> >  		qca->ibs_sent_slps++;
> > -
> > -		qca_wq_serial_tx_clock_vote_off(&qca->ws_tx_vote_off);
> >  		break;
> > 
> >  	case HCI_IBS_TX_ASLEEP:
> > @@ -2112,8 +2110,10 @@ static int __maybe_unused qca_suspend(struct
> > device *dev)
> >  			qca->rx_ibs_state == HCI_IBS_RX_ASLEEP,
> >  			msecs_to_jiffies(IBS_BTSOC_TX_IDLE_TIMEOUT_MS));
> > 
> > -	if (ret > 0)
> > +	if (ret > 0) {
> > +		qca_wq_serial_tx_clock_vote_off(&qca->ws_tx_vote_off);
> [Bala]: qca_wq_serial_tx_clock_vote_off votes for Tx clock off, when both Tx
> clock and Rx clock voted to off.
> then only actual call to clock off is called.
> https://elixir.bootlin.com/linux/latest/source/drivers/bluetooth/hci_qca.c#L312
> I would recommend to vote Tx clock off after sending SLEEP BYTE from HOST TO
> BT SOC.

Are you suggesting to move the vote after _wait_until_sent() and before
waiting for RX_SLEEP?

I think if the vote is done before RX_SLEEP and going to RX_SLEEP fails the
variables qca->tx_vote and qca->tx_votes_off would have the wrong state, even
if that doesn't lead to actually switching the clock off. I might be missing
something though, I'm not very familiar with this part.

Re: [PATCH 1/3] Bluetooth: hci_qca: Only remove TX clock vote after TX is completed

[Marcel Holtmann]

Hi Matthias,

> qca_suspend() removes the vote for the UART TX clock after
> writing an IBS sleep request to the serial buffer. This is
> not a good idea since there is no guarantee that the request
> has been sent at this point. Instead remove the vote after
> successfully entering IBS sleep. This also fixes the issue
> of the vote being removed in case of an aborted suspend due
> to a failure of entering IBS sleep.
> 
> Fixes: 41d5b25fed0a0 ("Bluetooth: hci_qca: add PM support")
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> ---
> 
> drivers/bluetooth/hci_qca.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)

patch has been applied to bluetooth-next tree.

Regards

Marcel

Re: [PATCH 2/3] Bluetooth: hci_qca: Skip serdev wait when no transfer is pending

[Marcel Holtmann]

Hi Matthias,

> qca_suspend() calls serdev_device_wait_until_sent() regardless of
> whether a transfer is pending. While it does no active harm since
> the function should return immediately it makes the code more
> confusing. Add a flag to track whether a transfer is pending and
> only call serdev_device_wait_until_sent() is needed.
> 
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> ---
> 
> drivers/bluetooth/hci_qca.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)

patch has been applied to bluetooth-next tree.

Regards

Marcel

Re: [PATCH 3/3] Bluetooth: hci_qca: Refactor error handling in qca_suspend()

[Marcel Holtmann]

Hi Matthias,

> If waiting for IBS sleep times out jump to the error handler, this is
> easier to read than multiple 'if' branches and a fall through to the
> error handler.
> 
> Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
> ---
> 
> drivers/bluetooth/hci_qca.c | 12 +++++-------
> 1 file changed, 5 insertions(+), 7 deletions(-)

patch has been applied to bluetooth-next tree.

Regards

Marcel