Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 1 | ========================== |
| 2 | Proc Files of ALSA Drivers |
| 3 | ========================== |
| 4 | |
| 5 | Takashi Iwai <tiwai@suse.de> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6 | |
| 7 | General |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 8 | ======= |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 9 | |
| 10 | ALSA has its own proc tree, /proc/asound. Many useful information are |
| 11 | found in this tree. When you encounter a problem and need debugging, |
| 12 | check the files listed in the following sections. |
| 13 | |
| 14 | Each card has its subtree cardX, where X is from 0 to 7. The |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 15 | card-specific files are stored in the ``card*`` subdirectories. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | |
| 17 | |
| 18 | Global Information |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 19 | ================== |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | |
| 21 | cards |
| 22 | Shows the list of currently configured ALSA drivers, |
| 23 | index, the id string, short and long descriptions. |
| 24 | |
| 25 | version |
| 26 | Shows the version string and compile date. |
| 27 | |
| 28 | modules |
| 29 | Lists the module of each card |
| 30 | |
| 31 | devices |
| 32 | Lists the ALSA native device mappings. |
| 33 | |
| 34 | meminfo |
| 35 | Shows the status of allocated pages via ALSA drivers. |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 36 | Appears only when ``CONFIG_SND_DEBUG=y``. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | |
| 38 | hwdep |
| 39 | Lists the currently available hwdep devices in format of |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 40 | ``<card>-<device>: <name>`` |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 41 | |
| 42 | pcm |
| 43 | Lists the currently available PCM devices in format of |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 44 | ``<card>-<device>: <id>: <name> : <sub-streams>`` |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | |
| 46 | timer |
| 47 | Lists the currently available timer devices |
| 48 | |
| 49 | |
| 50 | oss/devices |
| 51 | Lists the OSS device mappings. |
| 52 | |
| 53 | oss/sndstat |
| 54 | Provides the output compatible with /dev/sndstat. |
| 55 | You can symlink this to /dev/sndstat. |
| 56 | |
| 57 | |
| 58 | Card Specific Files |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 59 | =================== |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 60 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 61 | The card-specific files are found in ``/proc/asound/card*`` directories. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 62 | Some drivers (e.g. cmipci) have their own proc entries for the |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 63 | register dump, etc (e.g. ``/proc/asound/card*/cmipci`` shows the register |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 64 | dump). These files would be really helpful for debugging. |
| 65 | |
| 66 | When PCM devices are available on this card, you can see directories |
| 67 | like pcm0p or pcm1c. They hold the PCM information for each PCM |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 68 | stream. The number after ``pcm`` is the PCM device number from 0, and |
| 69 | the last ``p`` or ``c`` means playback or capture direction. The files in |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 70 | this subtree is described later. |
| 71 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 72 | The status of MIDI I/O is found in ``midi*`` files. It shows the device |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 73 | name and the received/transmitted bytes through the MIDI device. |
| 74 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 75 | When the card is equipped with AC97 codecs, there are ``codec97#*`` |
Matt LaPlante | fff9289 | 2006-10-03 22:47:42 +0200 | [diff] [blame] | 76 | subdirectories (described later). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 77 | |
| 78 | When the OSS mixer emulation is enabled (and the module is loaded), |
| 79 | oss_mixer file appears here, too. This shows the current mapping of |
| 80 | OSS mixer elements to the ALSA control elements. You can change the |
| 81 | mapping by writing to this device. Read OSS-Emulation.txt for |
| 82 | details. |
| 83 | |
| 84 | |
| 85 | PCM Proc Files |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 86 | ============== |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 87 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 88 | ``card*/pcm*/info`` |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 89 | The general information of this PCM device: card #, device #, |
| 90 | substreams, etc. |
| 91 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 92 | ``card*/pcm*/xrun_debug`` |
| 93 | This file appears when ``CONFIG_SND_DEBUG=y`` and |
| 94 | ``CONFIG_PCM_XRUN_DEBUG=y``. |
Takashi Iwai | 4f64e15 | 2009-06-11 16:14:11 +0200 | [diff] [blame] | 95 | This shows the status of xrun (= buffer overrun/xrun) and |
| 96 | invalid PCM position debug/check of ALSA PCM middle layer. |
| 97 | It takes an integer value, can be changed by writing to this |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 98 | file, such as:: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 99 | |
Masanari Iida | fdfa682 | 2009-12-27 00:09:45 +0900 | [diff] [blame] | 100 | # echo 5 > /proc/asound/card0/pcm0p/xrun_debug |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 101 | |
Takashi Iwai | 4f64e15 | 2009-06-11 16:14:11 +0200 | [diff] [blame] | 102 | The value consists of the following bit flags: |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 103 | |
| 104 | * bit 0 = Enable XRUN/jiffies debug messages |
| 105 | * bit 1 = Show stack trace at XRUN / jiffies check |
| 106 | * bit 2 = Enable additional jiffies check |
Takashi Iwai | 4f64e15 | 2009-06-11 16:14:11 +0200 | [diff] [blame] | 107 | |
| 108 | When the bit 0 is set, the driver will show the messages to |
| 109 | kernel log when an xrun is detected. The debug message is |
| 110 | shown also when the invalid H/W pointer is detected at the |
| 111 | update of periods (usually called from the interrupt |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 112 | handler). |
| 113 | |
Takashi Iwai | 4f64e15 | 2009-06-11 16:14:11 +0200 | [diff] [blame] | 114 | When the bit 1 is set, the driver will show the stack trace |
| 115 | additionally. This may help the debugging. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 116 | |
Takashi Iwai | 4f64e15 | 2009-06-11 16:14:11 +0200 | [diff] [blame] | 117 | Since 2.6.30, this option can enable the hwptr check using |
Takashi Iwai | c87d973 | 2009-05-27 10:53:33 +0200 | [diff] [blame] | 118 | jiffies. This detects spontaneous invalid pointer callback |
| 119 | values, but can be lead to too much corrections for a (mostly |
| 120 | buggy) hardware that doesn't give smooth pointer updates. |
Takashi Iwai | 4f64e15 | 2009-06-11 16:14:11 +0200 | [diff] [blame] | 121 | This feature is enabled via the bit 2. |
Takashi Iwai | c87d973 | 2009-05-27 10:53:33 +0200 | [diff] [blame] | 122 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 123 | ``card*/pcm*/sub*/info`` |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 124 | The general information of this PCM sub-stream. |
| 125 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 126 | ``card*/pcm*/sub*/status`` |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 127 | The current status of this PCM sub-stream, elapsed time, |
| 128 | H/W position, etc. |
| 129 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 130 | ``card*/pcm*/sub*/hw_params`` |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 131 | The hardware parameters set for this sub-stream. |
| 132 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 133 | ``card*/pcm*/sub*/sw_params`` |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 134 | The soft parameters set for this sub-stream. |
| 135 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 136 | ``card*/pcm*/sub*/prealloc`` |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 137 | The buffer pre-allocation information. |
| 138 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 139 | ``card*/pcm*/sub*/xrun_injection`` |
Takashi Iwai | 2b30d41 | 2014-11-04 14:02:40 +0100 | [diff] [blame] | 140 | Triggers an XRUN to the running stream when any value is |
| 141 | written to this proc file. Used for fault injection. |
| 142 | This entry is write-only. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 143 | |
| 144 | AC97 Codec Information |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 145 | ====================== |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 146 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 147 | ``card*/codec97#*/ac97#?-?`` |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 148 | Shows the general information of this AC97 codec chip, such as |
| 149 | name, capabilities, set up. |
| 150 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 151 | ``card*/codec97#0/ac97#?-?+regs`` |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 152 | Shows the AC97 register dump. Useful for debugging. |
| 153 | |
| 154 | When CONFIG_SND_DEBUG is enabled, you can write to this file for |
| 155 | changing an AC97 register directly. Pass two hex numbers. |
| 156 | For example, |
| 157 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 158 | :: |
| 159 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 160 | # echo 02 9f1f > /proc/asound/card0/codec97#0/ac97#0-0+regs |
| 161 | |
| 162 | |
Takashi Iwai | 59de641 | 2005-11-17 11:05:34 +0100 | [diff] [blame] | 163 | USB Audio Streams |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 164 | ================= |
Takashi Iwai | 59de641 | 2005-11-17 11:05:34 +0100 | [diff] [blame] | 165 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 166 | ``card*/stream*`` |
Takashi Iwai | 59de641 | 2005-11-17 11:05:34 +0100 | [diff] [blame] | 167 | Shows the assignment and the current status of each audio stream |
| 168 | of the given card. This information is very useful for debugging. |
| 169 | |
| 170 | |
| 171 | HD-Audio Codecs |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 172 | =============== |
Takashi Iwai | 59de641 | 2005-11-17 11:05:34 +0100 | [diff] [blame] | 173 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 174 | ``card*/codec#*`` |
Takashi Iwai | 59de641 | 2005-11-17 11:05:34 +0100 | [diff] [blame] | 175 | Shows the general codec information and the attribute of each |
| 176 | widget node. |
| 177 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 178 | ``card*/eld#*`` |
Wu Fengguang | a5fcf89 | 2008-11-22 09:40:55 +0800 | [diff] [blame] | 179 | Available for HDMI or DisplayPort interfaces. |
| 180 | Shows ELD(EDID Like Data) info retrieved from the attached HDMI sink, |
| 181 | and describes its audio capabilities and configurations. |
| 182 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 183 | Some ELD fields may be modified by doing ``echo name hex_value > eld#*``. |
Wu Fengguang | a5fcf89 | 2008-11-22 09:40:55 +0800 | [diff] [blame] | 184 | Only do this if you are sure the HDMI sink provided value is wrong. |
| 185 | And if that makes your HDMI audio work, please report to us so that we |
| 186 | can fix it in future kernel releases. |
| 187 | |
Takashi Iwai | 59de641 | 2005-11-17 11:05:34 +0100 | [diff] [blame] | 188 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 189 | Sequencer Information |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 190 | ===================== |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 191 | |
| 192 | seq/drivers |
| 193 | Lists the currently available ALSA sequencer drivers. |
| 194 | |
| 195 | seq/clients |
Matt LaPlante | 53cb472 | 2006-10-03 22:55:17 +0200 | [diff] [blame] | 196 | Shows the list of currently available sequencer clients and |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 197 | ports. The connection status and the running status are shown |
| 198 | in this file, too. |
| 199 | |
| 200 | seq/queues |
Matt LaPlante | 53cb472 | 2006-10-03 22:55:17 +0200 | [diff] [blame] | 201 | Lists the currently allocated/running sequencer queues. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | |
| 203 | seq/timer |
| 204 | Lists the currently allocated/running sequencer timers. |
| 205 | |
| 206 | seq/oss |
| 207 | Lists the OSS-compatible sequencer stuffs. |
| 208 | |
| 209 | |
| 210 | Help For Debugging? |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 211 | =================== |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 212 | |
| 213 | When the problem is related with PCM, first try to turn on xrun_debug |
| 214 | mode. This will give you the kernel messages when and where xrun |
| 215 | happened. |
| 216 | |
Matt LaPlante | d6bc8ac | 2006-10-03 22:54:15 +0200 | [diff] [blame] | 217 | If it's really a bug, report it with the following information: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 218 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 219 | - the name of the driver/card, show in ``/proc/asound/cards`` |
| 220 | - the register dump, if available (e.g. ``card*/cmipci``) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 221 | |
| 222 | when it's a PCM problem, |
| 223 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 224 | - set-up of PCM, shown in hw_parms, sw_params, and status in the PCM |
| 225 | sub-stream directory |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 226 | |
| 227 | when it's a mixer problem, |
| 228 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 229 | - AC97 proc files, ``codec97#*/*`` files |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 230 | |
| 231 | for USB audio/midi, |
| 232 | |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 233 | - output of ``lsusb -v`` |
| 234 | - ``stream*`` files in card directory |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 235 | |
| 236 | |
| 237 | The ALSA bug-tracking system is found at: |
Takashi Iwai | afb8fd3 | 2016-11-09 15:52:06 +0100 | [diff] [blame] | 238 | https://bugtrack.alsa-project.org/alsa-bug/ |