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From: Pavel Machek <pavel@ucw.cz>
To: Pali Roh??r <pali.rohar@gmail.com>
Cc: Marcel Holtmann <marcel@holtmann.org>,
	Luiz Augusto von Dentz <luiz.dentz@gmail.com>,
	"linux-bluetooth@vger.kernel.org"
	<linux-bluetooth@vger.kernel.org>,
	Johan Hedberg <johan.hedberg@gmail.com>
Subject: Re: HCI Set custom bandwidth for AuriStream SCO codec
Date: Tue, 12 Nov 2019 22:06:33 +0100
Message-ID: <20191112210633.cjhpb7eczzta63mf@ucw.cz> (raw)
In-Reply-To: <20191027220945.wmb3g55wtrmqbnmz@pali>

Hi!

> > > >>>>>>>> But for AuriStream I need to set custom SCO parameters as described
> > > >>>>>>>> below and currently kernel does not support it. This is why I'm asking
> > > >>>>>>>> how kernel can export for userspace configuration of SCO parameters...
> > > >>>>>>> 
> > > >>>>>>> We can always come up with socket options but we got to see the value
> > > >>>>>>> it would bring since AuriStream don't look that popular among
> > > >>>>>>> headsets, at least Ive never seem any device advertising it like
> > > >>>>>>> apt-X, etc.
> > > >>>>>> 
> > > >>>>>> Pali clearly has such device and he is willing to work on it. Surely
> > > >>>>>> that means it is popular enough to be supported...?
> > > >>>>> 
> > > >>>>> Just put AT+CSRSF=0,0,0,0,0,7 to google search and you would see that
> > > >>>>> not only I have such device...
> > > >>>>> 
> > > >>>>> So I would really would like to see that kernel finally stops blocking
> > > >>>>> usage of this AuriStream codec.
> > > >>>> 
> > > >>>> we need to figure out on how we do the kernel API to allow you this specific setting.
> > > >>> 
> > > >>> Hi Marcel! Kernel API for userspace should be simple. Just add two
> > > >>> ioctls for retrieving and setting structure with custom parameters:
> > > >>> 
> > > >>> syncPktTypes = 0x003F
> > > >>> bandwidth = 4000
> > > >>> max_latency = 16
> > > >>> voice_settings = 0x63
> > > >>> retx_effort = 2
> > > >>> 
> > > >>> Or add more ioctls, one ioctl per parameter. There is already only ioctl
> > > >>> for voice settings and moreover it is whitelisted only for two values.
> > > >> 
> > > >> it is not that simple actually. Most profiles define a certain set of parameters and then they try to configure better settings and only fallback to a specification defined default as last resort.
> > > > 
> > > > Ok. I see that there is another "example" configuration for AuriStream
> > > > with just different syncPktTypes = 0x02BF and bandwidth = 3850.
> > > > 
> > > > So it really is not simple as it can be seen.
> > > 
> > > currently the stepping for mSBC and CVSD are hard-coded in esco_param_cvsd and esco_param_msbc arrays in hci_conn.c and then selected by the ->setting parameter.
> > > 
> > > So either we provide an new socket option (for example BT_VOICE_EXT) or we extend BT_VOICE to allow providing the needed information. However this needs to be flexible array size since we should then be able to encode multiple stepping that are tried in order.
> > > 
> > > My preference is that we extend BT_VOICE and not introduce a new socket option. So feel free to propose how we can load the full tables into the SCO socket. I mean we are not really far off actually. The only difference is that currently the tables are in the hci_conn.c file and selected by the provided voice->setting. However nothing really stops us from providing the full table via user space.
> > 
> > Ok. I will look at it and I will try to propose how to extend current
> > BT_VOICE ioctl API for supporting all those new parameters.
> 
> Below is inline MIME part with POC patch which try to implement a new
> IOCTL (currently named BT_VOICE_SETUP) for configuring voice sco
> settings.
> 
> It uses flexible array of parameters <tx_bandwidth, rx_bandwidth,
> voice_setting, pkt_type, max_latency, retrans_effort>, but with
> maximally 10 array members (due to usage of static array storage). cvsd
> codec uses 7 different fallback settings (see voice_setup_cvsd), so for
> POC 10 should be enough.
> 
> Because a new IOCL has different members then old BT_VOICE I rather
> decided to introduce a new IOCTL and not hacking old IOCTL to accept two
> different structures.
> 
> Please let me know what do you think about this API, if this is a way
> how to continue or if something different is needed.


New ioctl sounds like good idea.

> diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h
> index fabee6db0abb..0e9f4ac07220 100644
> --- a/include/net/bluetooth/bluetooth.h
> +++ b/include/net/bluetooth/bluetooth.h
> @@ -122,6 +122,19 @@ struct bt_voice {
>  #define BT_SNDMTU		12
>  #define BT_RCVMTU		13
>  
> +#define BT_VOICE_SETUP		14
> +#define BT_VOICE_SETUP_ARRAY_SIZE 10
> +struct bt_voice_setup {
> +	__u8 sco_capable:1;
> +	__u8 esco_capable:1;
> +	__u32 tx_bandwidth;
> +	__u32 rx_bandwidth;
> +	__u16 voice_setting;
> +	__u16 pkt_type;
> +	__u16 max_latency;
> +	__u8 retrans_effort;
> +};
> +

Is this the new ioctl? I'd assume it should go to include/user/..
somewhere to be exported to userspace...?

Is it good idea to use __u8 :1 in user<->kernel API?

								Pavel



  reply index

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-04 17:15 Pali Rohár
2019-05-06 15:16 ` Pali Rohár
2019-05-16 18:34   ` Pali Rohár
2019-05-19  8:16     ` Luiz Augusto von Dentz
2019-05-19  8:23       ` Pali Rohár
2019-05-19  8:45         ` Luiz Augusto von Dentz
2019-05-19  8:54           ` Pali Rohár
2019-05-19 21:21           ` Pavel Machek
2019-06-07 13:02             ` Pali Rohár
2019-06-07 15:19               ` Luiz Augusto von Dentz
2019-07-06 13:45               ` Marcel Holtmann
2019-07-08 12:25                 ` Pali Rohár
2019-07-08 13:23                   ` Marcel Holtmann
2019-07-08 21:06                     ` Pali Rohár
2019-07-12 18:59                       ` Marcel Holtmann
2019-07-18 10:09                         ` Pali Rohár
2019-07-18 20:06                           ` Marcel Holtmann
2019-11-21 23:00                             ` Pali Rohár
2019-11-24 11:02                               ` Marcel Holtmann
2019-10-27 22:09                           ` Pali Rohár
2019-11-12 21:06                             ` Pavel Machek [this message]
2019-11-13  9:22                               ` Pali Rohár
2019-11-21 22:47                                 ` Pali Rohár
2019-11-19 17:04                             ` Marcel Holtmann
2019-11-19 17:13                               ` Pali Rohár
2019-11-19 23:47                                 ` Marcel Holtmann
2019-11-20  7:44                                   ` Pali Rohár
2019-11-21 22:44                                     ` Pali Rohár
2019-11-24 11:04                                       ` Marcel Holtmann
2019-11-24 11:13                                         ` Pali Rohár
2019-11-26  7:24                                           ` Marcel Holtmann
2019-11-26  7:46                                             ` Pali Rohár
2019-11-26  7:58                                               ` Marcel Holtmann
2019-11-26  8:00                                                 ` Pali Rohár
2019-11-26  9:41                                                   ` Luiz Augusto von Dentz
2019-11-26  9:58                                                     ` Pali Rohár
2019-12-05  9:28                                                       ` Pali Rohár
2019-12-11 14:40                                                         ` Pali Rohár
2020-01-04 10:04                                                         ` Marcel Holtmann
2020-01-04 10:37                                                           ` Pali Rohár
2020-02-09 12:59                                                             ` Pali Rohár
2020-02-19 12:09                                                           ` David Heidelberg
2020-04-19 23:49                                                             ` Bluetooth: Allow to use configure SCO socket codec parameters Pali Rohár
2020-04-20 23:54                                                               ` Luiz Augusto von Dentz
2020-04-21  8:53                                                                 ` Pali Rohár
2020-05-14 19:49                                                               ` Aleksandar Kostadinov
2020-05-15 22:46                                                                 ` Andrew Fuller
2020-05-15 23:08                                                                   ` Luiz Augusto von Dentz
2020-05-16  7:50                                                                     ` Aleksandar Kostadinov
2020-05-16  7:53                                                                     ` Pali Rohár
2020-05-18 16:43                                                                       ` Luiz Augusto von Dentz
2020-05-18 16:50                                                                         ` Pali Rohár
2020-05-27 12:18                                                                           ` Ujjwal Sharma
2020-05-27 15:48                                                                             ` Luiz Augusto von Dentz
2020-05-27 16:24                                                                               ` Ujjwal Sharma
2020-06-04 20:43                                                                                 ` Pali Rohár

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