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Date: Thu, 13 Jan 2011 01:53:07 -0500
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Subject: Re: Any flag indicating bt/fm is ready to run "hcitool cmd"
From: zhangfei gao <zhangfei.gao@gmail.com>
To: Johan Hedberg <johan.hedberg@gmail.com>,
	linux-bluetooth@vger.kernel.org
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On Wed, Jan 12, 2011 at 3:37 AM, Johan Hedberg <johan.hedberg@gmail.com> wrote:
> Hi,
>
> On Wed, Jan 12, 2011, zhangfei gao wrote:
>> Is there any flag indicating bt/fm is ready to run "hcitool cmd", ie,
>> "hciconfig hci0 up" is really finished.
>>
>> We met error "Send failed: File descriptor in bad state", if run
>> hcitool immediately after "hciconfig hci0 up"
>> For example:
>> hciconfig hci0 up
>> hcitool cmd 3f 66 02 26 00 00 00 30
>
> The HCIDEVUP ioctl is at least synchronized with the open() callback for
> the HCI driver so in that sense if the driver is working fine it should
> be possible to send commands when it returns. There is however an issue
> with existing kernels that HCIDEVUP doesn't wait for all of the kernels
> own HCI commands to finish before returning to user space. There was a
> patch sent for this some time ago which you might be interested in
> trying: http://marc.info/?l=linux-bluetooth&m=129296529630642&w=4

Really thanks Johan,
The patch synchronize hci_dev_open, it solve the problem we met, and
"hcitool cmd" could immediately send after "hciconfig hci0 up" without
problem.
By the way, is this patch already in the kernel?

>
> Johan
>