diff options
Diffstat (limited to 'Documentation/sound')
| -rw-r--r-- | Documentation/sound/alsa/Procfile.txt | 36 |
1 files changed, 22 insertions, 14 deletions
diff --git a/Documentation/sound/alsa/Procfile.txt b/Documentation/sound/alsa/Procfile.txt index cfac20cf9e3..381908d8ca4 100644 --- a/Documentation/sound/alsa/Procfile.txt +++ b/Documentation/sound/alsa/Procfile.txt | |||
| @@ -88,26 +88,34 @@ card*/pcm*/info | |||
| 88 | substreams, etc. | 88 | substreams, etc. |
| 89 | 89 | ||
| 90 | card*/pcm*/xrun_debug | 90 | card*/pcm*/xrun_debug |
| 91 | This file appears when CONFIG_SND_DEBUG=y. | 91 | This file appears when CONFIG_SND_DEBUG=y and |
| 92 | This shows the status of xrun (= buffer overrun/xrun) debug of | 92 | CONFIG_PCM_XRUN_DEBUG=y. |
| 93 | ALSA PCM middle layer, as an integer from 0 to 2. The value | 93 | This shows the status of xrun (= buffer overrun/xrun) and |
| 94 | can be changed by writing to this file, such as | 94 | invalid PCM position debug/check of ALSA PCM middle layer. |
| 95 | 95 | It takes an integer value, can be changed by writing to this | |
| 96 | # cat 2 > /proc/asound/card0/pcm0p/xrun_debug | 96 | file, such as |
| 97 | 97 | ||
| 98 | When this value is greater than 0, the driver will show the | 98 | # cat 5 > /proc/asound/card0/pcm0p/xrun_debug |
| 99 | messages to kernel log when an xrun is detected. The debug | 99 | |
| 100 | message is shown also when the invalid H/W pointer is detected | 100 | The value consists of the following bit flags: |
| 101 | at the update of periods (usually called from the interrupt | 101 | bit 0 = Enable XRUN/jiffies debug messages |
| 102 | bit 1 = Show stack trace at XRUN / jiffies check | ||
| 103 | bit 2 = Enable additional jiffies check | ||
| 104 | |||
| 105 | When the bit 0 is set, the driver will show the messages to | ||
| 106 | kernel log when an xrun is detected. The debug message is | ||
| 107 | shown also when the invalid H/W pointer is detected at the | ||
| 108 | update of periods (usually called from the interrupt | ||
| 102 | handler). | 109 | handler). |
| 103 | 110 | ||
| 104 | When this value is greater than 1, the driver will show the | 111 | When the bit 1 is set, the driver will show the stack trace |
| 105 | stack trace additionally. This may help the debugging. | 112 | additionally. This may help the debugging. |
| 106 | 113 | ||
| 107 | Since 2.6.30, this option also enables the hwptr check using | 114 | Since 2.6.30, this option can enable the hwptr check using |
| 108 | jiffies. This detects spontaneous invalid pointer callback | 115 | jiffies. This detects spontaneous invalid pointer callback |
| 109 | values, but can be lead to too much corrections for a (mostly | 116 | values, but can be lead to too much corrections for a (mostly |
| 110 | buggy) hardware that doesn't give smooth pointer updates. | 117 | buggy) hardware that doesn't give smooth pointer updates. |
| 118 | This feature is enabled via the bit 2. | ||
| 111 | 119 | ||
| 112 | card*/pcm*/sub*/info | 120 | card*/pcm*/sub*/info |
| 113 | The general information of this PCM sub-stream. | 121 | The general information of this PCM sub-stream. |