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

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