Return-Path: MIME-Version: 1.0 Date: Fri, 20 May 2016 11:18:12 +1000 Message-ID: Subject: How to setup the voice setting and sco-over-pcm parameters properly for bcm4356? From: Qingtao Cao To: linux-bluetooth@vger.kernel.org, Qingtao Cao Content-Type: text/plain; charset=UTF-8 Sender: linux-bluetooth-owner@vger.kernel.org List-ID: Hello Community, I had a trouble to set sco-over-pcm properly and couldn't hear sound properly through a connect bluetooth headset. With sco-over-hci, I could just hear some noise. I've got a htc m9 phone with bcm4356 as wifi/bt/fm chipset. Currently I have enabled the hci0 for it with the the help of brcm_patchram_plus program which has an "--scopcm" option to setup the hardware pcm interface and the pcm frame format with the following sub-parameters: #1 sco_routing 0 for PCM, 1 for Transport, 2 for Codec and 3 for I2S #2 pcm_interface_rate 0 for 128k, 1 for 256k, 2 for 512k, 3 for 1034k, 4 for 2048k #3 frame_type 0 for short, 1 for long #4 sync_mode 0 for slave, 1 for master #5 clock_mode 0 for slave and 1 for master #6 lsb_first 0 for false and 1 for true #7 fill_bits the value in decimal for unused bits #8 fill_method 0 for 0's, 1 for 1's, 2 for signed and 3 for programmable #9 fill_num the number or bits to be filled #10 right_justify 0 for false and 1 for true Broadcom's libbt-vendor.so implementation for bluedroid set it up as "0,4,0,0,0,0,0,3,0,0", since the first sco_routing == 0，the pcm data is routed into the pcm interface instead of through HCI-UART interface. I have enabled SCORouting = PCM in audio.conf, however, I can't hear anything at all through my connected bluetooth headset using the HSP/HFP profiles. However, if I change the sco_routing byte to 1 and SCORouting = HCI, that is, to route pcm data from the HCI-UART interface instead of the hardware pcm interface, I could hear some noise from my connected bluetooth headset. I also tried with different sample rate but failed to have them played properly. BTW, if I use A2DP profile I can play mp3 file well through a bluetooth speaker. Currently the voice setting for my hci0 is the default value of 0x0060 / # hciconfig hci0 voice hci0: Type: BR/EDR Bus: UART BD Address: 90:E7:C4:F3:F7:09 ACL MTU: 1021:8 SCO MTU: 64:1 Voice setting: 0x0060 (Default Condition) Input Coding: Linear Input Data Format: 2's complement Input Sample Size: 16 bit # of bits padding at MSB: 0 Air Coding Format: CVSD So how could I set below options: #1 above parameters of input coding, input data format, input sample size etc, and #2 the sample rate and format settings when recording the audio file (used by arecord for example), and #3 the --scopcm option of the brcm_patchram_plus program in accordance with each other to make both sco-over-hci and sco-over-pcm work? Last but not least, suppose the to be played .wav file is of a different sample rate or format settings than what has been set through the --scopcm option, should the music player or audio server convert it to the expected format before writing to sco socket? Many thanks for any comments or advices! Cheers, Harry