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    SubjectRe: [PATCH v5] Bluetooth: btwilink driver
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    On Wed, Nov 17, 2010 at 10:22 PM, Gustavo F. Padovan
    <padovan@profusion.mobi> wrote:
    > Hi Pavan,
    >
    > * Pavan Savoy <pavan_savoy@sify.com> [2010-11-17 11:13:26 +0530]:
    >
    >> On Wed, Nov 17, 2010 at 4:50 AM, Vitaly Wool <vitalywool@gmail.com> wrote:
    >> >>> +     /* Registration with ST layer is successful,
    >> >>> +      * hardware is ready to accept commands from HCI core.
    >> >>> +      */
    >> >>> +     if (test_and_set_bit(HCI_RUNNING, &hdev->flags)) {
    >> >>> +             clear_bit(HCI_RUNNING, &hdev->flags);
    >> >>> +             err = st_unregister(ST_BT);
    >> >>> +             if (err)
    >> >>> +                     BT_ERR("st_unregister() failed with error %d", err);
    >> >>> +             hst->st_write = NULL;
    >> >>> +     }
    >> >>
    >> >>
    >> >> What are you trying to do here? test_and_set_bit() result doesn't say
    >> >> nothing about error and you shall put test_and_set_bit should be in the
    >> >> beginning, to know if your device is already opened or not and then
    >> >> clear_bit if some error ocurrs during the function.
    >> >>
    >> >
    >> > Yeap, this piece of code beats me is well. Why is it an error if this
    >> > bit wasn't already set?
    >>
    >> Vitaly, Gustavo,
    >>
    >> I suppose I never understood HCI_RUNNING flag that way, as in an error
    >> check mechanism to avoid multiple hci0 ups.
    >>
    >> What I understood was that HCI_RUNNING suggested as to when hci0 was
    >> ready to be used. With this understanding, I wanted to make sure I
    >> downloaded the firmware for the chip before I proclaim to the world
    >> that the hci0 is ready to be used, as in HCI_RUNNING.
    >>
    >> For example, I didn't want my _send_frame to be called before I did
    >> the firmware download - since firmware download takes time - 45kb
    >> send/wait commands :(
    >>
    >> But I suppose I now understand - What I would rather do is test_bit in
    >> the beginning of function and do a set_bit at the end of function -
    >> does this make sense ?
    >
    > It does, but does it as test_and_set and then clear if error as we do in
    > other drivers.

    Ok, I understand, will do it this way.
    However, still I am not too convinced - I honestly don't want to set
    HCI_RUNNING before firmware download required for WiLink happens - and
    this happens inside the st_register function here.

    So the question again, How can I ensure _send_frame is not called when
    firmware download is in progress - one of the major reasons why I
    delayed the setting of HCI_RUNNING.

    As mentioned before I will go ahead and create the patch - But would
    still like to have an answer to this.


    > Gustavo F. Padovan
    > http://profusion.mobi
    >
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