!!################################ !!ALSA Information Script v 0.4.63 !!################################ !!Script ran on: Tue Aug 26 12:04:17 UTC 2014 !!Linux Distribution !!------------------ Ubuntu 12.04.4 LTS \n \l DISTRIB_ID=Ubuntu DISTRIB_DESCRIPTION="Ubuntu 12.04.4 LTS" NAME="Ubuntu" ID=ubuntu ID_LIKE=debian PRETTY_NAME="Ubuntu precise (12.04.4 LTS)" !!DMI Information !!--------------- Manufacturer: Product Name: Product Version: Firmware Version: !!Kernel Information !!------------------ Kernel release: 3.10.29op1 Operating System: GNU/Linux Architecture: i686 Processor: i686 SMP Enabled: Yes !!ALSA Version !!------------ Driver version: k3.10.29op1 Library version: 1.0.25 Utilities version: !!Loaded ALSA modules !!------------------- snd_hda_intel snd_usb_audio !!Sound Servers on this system !!---------------------------- No sound servers found. !!Soundcards recognised by ALSA !!----------------------------- 0 [MID ]: HDA-Intel - HDA Intel MID HDA Intel MID at 0xd01c0000 irq 16 1 [Audio ]: USB-Audio - USB2.0 High-Speed True HD Audio CMEDIA USB2.0 High-Speed True HD Audio at usb-0000:00:1d.7-4, high speed !!PCI Soundcards installed in the system !!-------------------------------------- 00:1b.0 Audio device: Intel Corporation System Controller Hub (SCH Poulsbo) HD Audio Controller (rev 07) !!Advanced information - PCI Vendor/Device/Subsystem ID's !!------------------------------------------------------- 00:1b.0 0403: 8086:811b (rev 07) Subsystem: 8086:8119 !!Modprobe options (Sound related) !!-------------------------------- snd-atiixp-modem: index=-2 snd-intel8x0m: index=-2 snd-via82xx-modem: index=-2 snd-usb-audio: index=-2 snd-usb-caiaq: index=-2 snd-usb-ua101: index=-2 snd-usb-us122l: index=-2 snd-usb-usx2y: index=-2 snd-cmipci: mpu_port=0x330 fm_port=0x388 snd-pcsp: index=-2 snd-usb-audio: index=-2 snd-hda-intel: position_fix=1 bdl_pos_adj=64 patch=of1-stac9202.patch !!Loaded sound module options !!--------------------------- !!Module: snd_hda_intel align_buffer_size : -1 bdl_pos_adj : 64,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1 beep_mode : N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N,N enable : Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y enable_msi : -1 id : (null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null) index : -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1 jackpoll_ms : 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 model : (null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null) patch : of1-stac9202.patch,(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null) position_fix : 1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1 power_save : 0 power_save_controller : Y probe_mask : -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1 probe_only : 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 single_cmd : N snoop : Y !!Module: snd_usb_audio autoclock : Y device_setup : 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 enable : Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y,Y id : (null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null),(null) ignore_ctl_error : N index : -2,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1 nrpacks : 8 pid : -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1 vid : -1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1,-1 !!HDA-Intel Codec information !!--------------------------- --startcollapse-- Codec: SigmaTel STAC9202 Address: 0 AFG Function Id: 0x1 (unsol 1) Vendor Id: 0x83847632 Subsystem Id: 0x00000100 Revision Id: 0x100101 No Modem Function Group found Default PCM: rates [0x7e0]: 44100 48000 88200 96000 176400 192000 bits [0xe]: 16 20 24 formats [0x1]: PCM Default Amp-In caps: N/A Default Amp-Out caps: ofs=0x1f, nsteps=0x1f, stepsize=0x05, mute=1 State of AFG node 0x01: Power states: D0 D1 D2 D3 Power: setting=D0, actual=D0 GPIO: io=4, o=0, i=0, unsolicited=1, wake=1 IO[0]: enable=0, dir=0, wake=0, sticky=0, data=0, unsol=0 IO[1]: enable=0, dir=0, wake=0, sticky=0, data=0, unsol=0 IO[2]: enable=0, dir=0, wake=0, sticky=0, data=0, unsol=0 IO[3]: enable=0, dir=0, wake=0, sticky=0, data=0, unsol=0 Node 0x02 [Audio Output] wcaps 0xd0401: Stereo Device: name="STAC9202 Analog", type="Audio", device=0 Converter: stream=0, channel=0 Power states: Power: setting=D0, actual=D0 Delay: 13 samples Node 0x03 [Audio Input] wcaps 0x1d0541: Stereo Device: name="STAC9202 Analog", type="Audio", device=0 Converter: stream=0, channel=0 SDI-Select: 0 Power states: Power: setting=D0, actual=D0 Delay: 13 samples Connection: 1 0x14 Processing caps: benign=0, ncoeff=0 Node 0x04 [Audio Input] wcaps 0x140311: Stereo Digital Converter: stream=0, channel=0 SDI-Select: 0 Digital: Digital category: 0x0 IEC Coding Type: 0x0 PCM: rates [0x160]: 44100 48000 96000 bits [0xe]: 16 20 24 formats [0x5]: PCM AC3 Delay: 4 samples Connection: 1 0x07 Node 0x05 [Audio Output] wcaps 0x40211: Stereo Digital Control: name="IEC958 Playback Con Mask", index=0, device=0 Control: name="IEC958 Playback Pro Mask", index=0, device=0 Control: name="IEC958 Playback Default", index=0, device=0 Control: name="IEC958 Playback Switch", index=0, device=0 Control: name="IEC958 Default PCM Playback Switch", index=0, device=0 Device: name="STAC9202 Digital", type="SPDIF", device=1 Converter: stream=0, channel=0 Digital: Digital category: 0x0 IEC Coding Type: 0x0 PCM: rates [0x1e0]: 44100 48000 88200 96000 bits [0xe]: 16 20 24 formats [0x5]: PCM AC3 Delay: 4 samples Node 0x06 [Audio Selector] wcaps 0x300901: Stereo R/L Connection: 3 0x02* 0x07 0x14 Node 0x07 [Pin Complex] wcaps 0x430681: Stereo Digital Pincap 0x00010024: IN EAPD Detect EAPD 0x2: EAPD Pin Default 0x01c5e150: [Jack] SPDIF In at Ext Rear Conn = Optical, Color = White DefAssociation = 0x5, Sequence = 0x0 Misc = NO_PRESENCE Pin-ctls: 0x00: Unsolicited: tag=00, enabled=0 Power states: Power: setting=D0, actual=D0 Delay: 3 samples Node 0x08 [Pin Complex] wcaps 0x400301: Stereo Digital Control: name="SPDIF Phantom Jack", index=0, device=0 Pincap 0x00000010: OUT Pin Default 0x01451130: [Jack] SPDIF Out at Ext Rear Conn = Optical, Color = Black DefAssociation = 0x3, Sequence = 0x0 Misc = NO_PRESENCE Pin-ctls: 0x40: OUT Connection: 2 0x05* 0x14 Node 0x09 [Audio Selector] wcaps 0x30010d: Stereo Amp-Out Control: name="Capture Volume", index=0, device=0 ControlAmp: chs=3, dir=Out, idx=0, ofs=0 Amp-Out caps: ofs=0x00, nsteps=0x0f, stepsize=0x05, mute=0 Amp-Out vals: [0x08 0x08] Connection: 1 0x0f Node 0x0a [Pin Complex] wcaps 0x400181: Stereo Control: name="Front Speaker Jack", index=0, device=0 Pincap 0x0000003f: IN OUT HP Detect Trigger ImpSense Pin Default 0x0221401f: [Jack] HP Out at Ext Front Conn = 1/8, Color = Green DefAssociation = 0x1, Sequence = 0xf Pin-ctls: 0x40: OUT Unsolicited: tag=06, enabled=1 Connection: 1 0x0e Node 0x0b [Pin Complex] wcaps 0x400181: Stereo Control: name="Mic Jack", index=0, device=0 Pincap 0x00001737: IN OUT Detect Trigger ImpSense Vref caps: HIZ 50 GRD 80 Pin Default 0x02a19020: [Jack] Mic at Ext Front Conn = 1/8, Color = Pink DefAssociation = 0x2, Sequence = 0x0 Pin-ctls: 0x24: IN VREF_80 Unsolicited: tag=02, enabled=1 Connection: 1 0x0e Node 0x0c [Pin Complex] wcaps 0x400181: Stereo Control: name="Line Jack", index=0, device=0 Pincap 0x00001737: IN OUT Detect Trigger ImpSense Vref caps: HIZ 50 GRD 80 Pin Default 0x01813021: [Jack] Line In at Ext Rear Conn = 1/8, Color = Blue DefAssociation = 0x2, Sequence = 0x1 Pin-ctls: 0x20: IN VREF_HIZ Unsolicited: tag=03, enabled=1 Connection: 1 0x0e Node 0x0d [Pin Complex] wcaps 0x400181: Stereo Control: name="Front Headphone Jack", index=0, device=0 Pincap 0x0000003f: IN OUT HP Detect Trigger ImpSense Pin Default 0x01014010: [Jack] Line Out at Ext Rear Conn = 1/8, Color = Green DefAssociation = 0x1, Sequence = 0x0 Pin-ctls: 0xc0: OUT HP Unsolicited: tag=01, enabled=1 Connection: 1 0x0e Node 0x0e [Audio Selector] wcaps 0x300105: Stereo Amp-Out Control: name="Headphone Playback Volume", index=0, device=0 ControlAmp: chs=3, dir=Out, idx=0, ofs=0 Control: name="Headphone Playback Switch", index=0, device=0 ControlAmp: chs=3, dir=Out, idx=0, ofs=0 Amp-Out caps: N/A Amp-Out vals: [0x11 0x11] Connection: 1 0x06 Node 0x0f [Audio Selector] wcaps 0x30010d: Stereo Amp-Out Control: name="Mic Boost Volume", index=0, device=0 ControlAmp: chs=3, dir=Out, idx=0, ofs=0 Amp-Out caps: ofs=0x00, nsteps=0x04, stepsize=0x27, mute=0 Amp-Out vals: [0x00 0x00] Connection: 5 0x0b* 0x0c 0x0d 0x0a 0x11 Node 0x10 [Pin Complex] wcaps 0x400104: Mono Amp-Out Control: name="PCM Playback Volume", index=0, device=0 ControlAmp: chs=1, dir=Out, idx=0, ofs=0 Control: name="PCM Playback Switch", index=0, device=0 ControlAmp: chs=1, dir=Out, idx=0, ofs=0 Control: name="Line Out Phantom Jack", index=0, device=0 Amp-Out caps: N/A Amp-Out vals: [0x11] Pincap 0x00000010: OUT Pin Default 0x500701f0: [N/A] Line Out at Int N/A Conn = Analog, Color = Unknown DefAssociation = 0xf, Sequence = 0x0 Misc = NO_PRESENCE Pin-ctls: 0x40: OUT Connection: 1 0x12 Node 0x11 [Pin Complex] wcaps 0x400001: Stereo Control: name="CD Phantom Jack", index=0, device=0 Pincap 0x00000020: IN Pin Default 0x90330122: [Fixed] CD at Int N/A Conn = ATAPI, Color = Unknown DefAssociation = 0x2, Sequence = 0x2 Misc = NO_PRESENCE Pin-ctls: 0x20: IN Node 0x12 [Audio Mixer] wcaps 0x200100: Mono Connection: 1 0x06 Node 0x13 [Beep Generator Widget] wcaps 0x70000c: Mono Amp-Out Amp-Out caps: ofs=0x03, nsteps=0x03, stepsize=0x17, mute=1 Amp-Out vals: [0x83] Node 0x14 [Audio Selector] wcaps 0x30090d: Stereo Amp-Out R/L Control: name="Capture Switch", index=0, device=0 ControlAmp: chs=3, dir=Out, idx=0, ofs=0 Amp-Out caps: ofs=0x00, nsteps=0x00, stepsize=0x00, mute=1 Amp-Out vals: [0x00 0x00] Connection: 2 0x09* 0x15 Node 0x15 [Pin Complex] wcaps 0x400001: Stereo Control: name="Digital In Phantom Jack", index=0, device=0 Pincap 0x00000020: IN Pin Default 0x50a001f1: [N/A] Mic at Int N/A Conn = Unknown, Color = Unknown DefAssociation = 0xf, Sequence = 0x1 Misc = NO_PRESENCE Pin-ctls: 0x00: --endcollapse-- !!USB Mixer information !!--------------------- --startcollapse-- USB Mixer: usb_id=0x147ae055, ctrlif=0, ctlerr=0 Card: CMEDIA USB2.0 High-Speed True HD Audio at usb-0000:00:1d.7-4, high speed Unit: 10 Control: name="PCM Capture Source", index=0 Info: id=10, control=0, cmask=0x0, channels=1, type="U8" Volume: min=1, max=3, dBmin=0, dBmax=0 Unit: 11 Control: name="Speaker Playback Volume", index=2 Info: id=11, control=2, cmask=0xff, channels=8, type="S16" Volume: min=-15872, max=0, dBmin=-6200, dBmax=0 Unit: 11 Control: name="Speaker Playback Switch", index=2 Info: id=11, control=1, cmask=0x0, channels=1, type="INV_BOOLEAN" Volume: min=0, max=1, dBmin=0, dBmax=0 Unit: 12 Control: name="IEC958 In Playback Switch", index=0 Info: id=12, control=1, cmask=0x0, channels=1, type="INV_BOOLEAN" Volume: min=0, max=1, dBmin=0, dBmax=0 Unit: 13 Control: name="Auto Gain Control", index=0 Info: id=13, control=7, cmask=0x0, channels=1, type="BOOLEAN" Volume: min=0, max=1, dBmin=0, dBmax=0 Unit: 13 Control: name="PCM Capture Volume", index=0 Info: id=13, control=2, cmask=0x3, channels=2, type="S16" Volume: min=-4096, max=3072, dBmin=-1600, dBmax=1200 Unit: 13 Control: name="PCM Capture Switch", index=0 Info: id=13, control=1, cmask=0x0, channels=1, type="INV_BOOLEAN" Volume: min=0, max=1, dBmin=0, dBmax=0 Unit: 14 Control: name="PCM Capture Volume", index=1 Info: id=14, control=2, cmask=0x3, channels=2, type="S16" Volume: min=-4096, max=3072, dBmin=-1600, dBmax=1200 Unit: 14 Control: name="PCM Capture Switch", index=1 Info: id=14, control=1, cmask=0x0, channels=1, type="INV_BOOLEAN" Volume: min=0, max=1, dBmin=0, dBmax=0 Unit: 15 Control: name="PCM Capture Volume", index=2 Info: id=15, control=2, cmask=0x3, channels=2, type="S16" Volume: min=-4096, max=3072, dBmin=-1600, dBmax=1200 Unit: 15 Control: name="PCM Capture Switch", index=2 Info: id=15, control=1, cmask=0x0, channels=1, type="INV_BOOLEAN" Volume: min=0, max=1, dBmin=0, dBmax=0 Unit: 16 Control: name="Speaker Playback Volume", index=0 Info: id=16, control=2, cmask=0x3, channels=2, type="S16" Volume: min=-8832, max=3072, dBmin=-3450, dBmax=1200 Unit: 16 Control: name="Speaker Playback Switch", index=0 Info: id=16, control=1, cmask=0x0, channels=1, type="INV_BOOLEAN" Volume: min=0, max=1, dBmin=0, dBmax=0 Unit: 17 Control: name="Speaker Playback Volume", index=1 Info: id=17, control=2, cmask=0x3, channels=2, type="S16" Volume: min=-8832, max=3072, dBmin=-3450, dBmax=1200 Unit: 17 Control: name="Speaker Playback Switch", index=1 Info: id=17, control=1, cmask=0x0, channels=1, type="INV_BOOLEAN" Volume: min=0, max=1, dBmin=0, dBmax=0 --endcollapse-- !!ALSA Device nodes !!----------------- crw-rw---T 1 root audio 116, 6 Aug 26 12:50 /dev/snd/controlC0 crw-rw---T 1 root audio 116, 12 Aug 26 12:50 /dev/snd/controlC1 crw-rw---T 1 root audio 116, 5 Aug 26 12:50 /dev/snd/hwC0D0 crw-rw---T 1 root audio 116, 4 Aug 26 12:50 /dev/snd/pcmC0D0c crw-rw---T 1 root audio 116, 3 Aug 26 12:50 /dev/snd/pcmC0D0p crw-rw---T 1 root audio 116, 2 Aug 26 12:50 /dev/snd/pcmC0D1p crw-rw---T 1 root audio 116, 11 Aug 26 12:50 /dev/snd/pcmC1D0c crw-rw---T 1 root audio 116, 10 Aug 26 12:50 /dev/snd/pcmC1D0p crw-rw---T 1 root audio 116, 9 Aug 26 12:50 /dev/snd/pcmC1D1c crw-rw---T 1 root audio 116, 8 Aug 26 12:50 /dev/snd/pcmC1D1p crw-rw---T 1 root audio 116, 7 Aug 26 12:50 /dev/snd/pcmC1D2p crw-rw---T 1 root audio 116, 1 Aug 26 12:50 /dev/snd/seq crw-rw---T 1 root audio 116, 33 Aug 26 12:50 /dev/snd/timer /dev/snd/by-id: total 0 drwxr-xr-x 2 root root 60 Aug 26 12:50 . drwxr-xr-x 4 root root 340 Aug 26 12:50 .. lrwxrwxrwx 1 root root 12 Aug 26 12:50 usb-CMEDIA_USB2.0_High-Speed_True_HD_Audio-00 -> ../controlC1 /dev/snd/by-path: total 0 drwxr-xr-x 2 root root 80 Aug 26 12:50 . drwxr-xr-x 4 root root 340 Aug 26 12:50 .. lrwxrwxrwx 1 root root 12 Aug 26 12:50 pci-0000:00:1b.0 -> ../controlC0 lrwxrwxrwx 1 root root 12 Aug 26 12:50 pci-0000:00:1d.7-usb-0:4:1.0 -> ../controlC1 !!ALSA configuration files !!------------------------ !!System wide config file (/etc/asound.conf) pcm.!default { type plug slave.pcm "dmixer" } pcm.dmixer { type dmix ipc_key 1024 slave { pcm "hw:1,0" period_time 0 period_size 1024 buffer_size 4096 rate 44100 } bindings { 0 0 1 1 } } ctl.dmixer { type hw card 1 } !!Aplay/Arecord output !!-------------------- APLAY alsa-info.sh: line 118: aplay: command not found ARECORD alsa-info.sh: line 122: arecord: command not found !!Amixer output !!------------- !!-------Mixer controls for card 0 [MID] alsa-info.sh: line 143: amixer: command not found alsa-info.sh: line 144: amixer: command not found !!-------Mixer controls for card 1 [Audio] alsa-info.sh: line 143: amixer: command not found alsa-info.sh: line 144: amixer: command not found !!Alsactl output !!-------------- --startcollapse-- --endcollapse-- !!All Loaded Modules !!------------------ Module snd_usb_audio snd_pcm_oss snd_hda_codec_idt snd_mixer_oss snd_hda_intel snd_seq_dummy snd_hda_codec snd_seq_oss snd_pcm snd_hwdep snd_usbmidi_lib microcode snd_seq_midi snd_rawmidi snd_seq_midi_event rt2870sta snd_seq joydev snd_timer snd_seq_device snd soundcore snd_page_alloc nls_iso8859_1 nls_cp437 vfat fat hid_generic usbhid hid r8169 mii gma500_gfx drm_kms_helper drm agpgart i2c_algo_bit video !!Sysfs Files !!----------- /sys/class/sound/hwC0D0/init_pin_configs: 0x07 0x01c5e150 0x08 0x01451130 0x0a 0x0221401f 0x0b 0x02a19020 0x0c 0x01813021 0x0d 0x01014010 0x10 0x500701f0 0x11 0x90330122 0x15 0x50a001f1 /sys/class/sound/hwC0D0/driver_pin_configs: /sys/class/sound/hwC0D0/user_pin_configs: 0x07 0x01110014 0x08 0x01410013 0x0a 0x02111011 0x0d 0x02214012 0x0c 0x01810022 0x0b 0x01a10021 0x10 0x01010031 0x11 0x01310023 0x15 0x01d10024 /sys/class/sound/hwC0D0/init_verbs: 0x06 0x701 0x0000 0x07 0x70c 0x0002 0x14 0x390 0x0000 0x14 0x3a0 0x0000 0x0f 0x707 0x0000 /sys/class/sound/hwC0D0/hints: !!ALSA/HDA dmesg !!-------------- microcode: CPU0 sig=0x106c2, pf=0x1, revision=0x20a snd_hda_intel 0000:00:1b.0: enabling device (0000 -> 0002) hda-intel 0000:00:1b.0: Applying patch firmware 'of1-stac9202.patch' input: HDA Intel MID Front Speaker as /devices/pci0000:00/0000:00:1b.0/sound/card0/input3 input: HDA Intel MID Front Headphone as /devices/pci0000:00/0000:00:1b.0/sound/card0/input4 input: HDA Intel MID Line as /devices/pci0000:00/0000:00:1b.0/sound/card0/input5 input: HDA Intel MID Mic as /devices/pci0000:00/0000:00:1b.0/sound/card0/input6 usb-audio:2: clock source 25 is not valid, cannot use usb-audio:2: clock source 25 is not valid, cannot use usbcore: registered new interface driver snd-usb-audio microcode: CPU1 sig=0x106c2, pf=0x1, revision=0x20a