Hi Pali, >>>>>>> to be honest, I would rather see WBS implementation finally >>>>>>> reach PA before we start digging into this. >>>>>> >>>>>> First I want to finish improving A2DP codec support in pulseaudio. Later >>>>>> I can look at HSP/HFP profiles. Ideally it should have modular/plugin >>>>>> extensible design. So the aim is that adding new codec would be very >>>>>> simple, without need to hack something related to mSBC/WBC, AuriStream >>>>>> or any other codec. >>>>> >>>>> Well HSP don't have support for codec negotiation, but yes a modular >>>>> design is probably recommended. >>>>> >>>>>> 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. >> We have kept is really simple since there was only CVSD and mSBC as of now. > > Seems that custom codecs are already widely used, so it would be great > it Linux kernel allows to use also other codecs in future without need > to explicitly whitelist them. This is an overstatement. I see only one custom codec being used. Unless you have heard from others. However as stated above, I think we need to provide an array of settings that are similar defined to what the HFP spec does. Then we just load the whole set into the kernel. >> I am also curious on what the assumptions are for the USB driver alternate settings are when using a different codec. > > I did all above tests and kernel changes with USB bluetooth chip which > is integrated in notebook's combo bt+wifi intel minipci-e card. Good to know. Since for mSBC in theory they need a new alternate settings that wasn’t really available. Regards Marcel
