On Fri, Aug 28, 2009 at 12:51 PM, Takashi Iwai <tiwai@xxxxxxx> wrote: > At Fri, 28 Aug 2009 11:29:52 -0700, > Bankim Bhavsar wrote: >> >> Takashi I came across a workaround for VMware in ALSA kernel code >> In the comments you mention about inaccurate timer source. >> Could you elaborate on the problem? > > The problem is that the irq timing emulated on vmware isn't always > accurate. The sound hardware is supposed to issue an irq at the > programmed buffer period. On VMware, this irq generation seems to be > done based on the system timer (or alike), thus it's not generated > at the accurate timing that the hardware should give. > > The driver has no idea whether it's on VM, thus assumed that the > IRQ must come accurately more or less. In the recent code, there are > some additions to correct the DMA position more to believe the accuracy > of the IRQ than the position calculated from the hardware register. > This caused a regression on VMware. My patch fixed that, at least, > for VMware in the stance of previous versions. Thanks for the explanation, Takashi. Sorry for the delayed response. I tested with the fix for VMware with 2.6.31rc9 kernel. Sound playback suffers from underruns and app terminates prematurely. I've attached the output of "aplay sample.wav -vvv". I compiled kernel with following config options turned on CONFIG_SND_DEBUG=y CONFIG_SND_DEBUG_VERBOSE=y CONFIG_SND_PCM_XRUN_DEBUG=y and set /proc/asound/card0/pcm0p/xrun_debug to 1. I can't seem to find ALSA xrun_debug log messages with dmesg. Am I looking in the wrong place? As far as the timing of sound IRQ goes, with our emulation of ENS1371 delay in firing interrupt ranges from 50-500 usecs. Is that large enough to cause xruns with recent changes? Linux guests with kernel version 2.6.31+ running under VMware are affected currently. Let me know if you need more information. >> Is there something specific you would like us to fix in our virtual >> sound device or timer source? > > Well, the only question is how can we get the programmed sound IRQ > more accurately... If hrtimer with the fine timer source is available, > this could be emulated well, I guess. I'll consult our timer experts in VMware and get back to you on this question. -- Bankim.
Playing WAVE 'sample.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Stereo ALSA <-> PulseAudio PCM I/O Plugin Its setup is: stream : PLAYBACK access : RW_INTERLEAVED format : S16_LE subformat : STD channels : 2 rate : 48000 exact rate : 48000 (48000/1) msbits : 16 buffer_size : 24000 period_size : 6000 period_time : 125000 tstamp_mode : NONE period_step : 1 avail_min : 6000 period_event : 0 start_threshold : 24000 stop_threshold : 24000 silence_threshold: 0 silence_size : 0 boundary : 1572864000 underrun!!! (at least 10.708 ms long) Status: state : XRUN trigger_time: 1252864094.528012000 tstamp : 0.000000 delay : 0 avail : 5499 avail_max : 24000 underrun!!! (at least 34.164 ms long) Status: state : XRUN trigger_time: 1252864094.551488000 tstamp : 0.000000 delay : 0 avail : 369 avail_max : 24369 underrun!!! (at least 31.420 ms long) Status: state : XRUN trigger_time: 1252864094.598043000 tstamp : 0.000000 delay : 0 avail : 5499 avail_max : 24000 underrun!!! (at least 20.394 ms long) Status: state : XRUN trigger_time: 1252864094.648311000 tstamp : 0.000000 delay : 0 avail : 5499 avail_max : 24000 underrun!!! (at least 26.042 ms long) Status: state : XRUN trigger_time: 1252864094.690683000 tstamp : 0.000000 delay : 0 avail : 369 avail_max : 24000 underrun!!! (at least 18.061 ms long) Status: state : XRUN trigger_time: 1252864094.730349000 tstamp : 0.000000 delay : 0 avail : 12369 avail_max : 24369 underrun!!! (at least 368.755 ms long) Status: state : XRUN trigger_time: 1252864094.761685000 tstamp : 0.000000 delay : 0 avail : 5499 avail_max : 26488 underrun!!! (at least 6.058 ms long) Status: state : XRUN trigger_time: 1252864095.150158000 tstamp : 0.000000 delay : 0 avail : 5499 avail_max : 24000 underrun!!! (at least 360.790 ms long) Status: state : XRUN trigger_time: 1252864095.168713000 tstamp : 0.000000 delay : 0 avail : 17852 avail_max : 29072 underrun!!! (at least 18.394 ms long) Status: state : XRUN trigger_time: 1252864095.550346000 tstamp : 0.000000 delay : 0 avail : 5499 avail_max : 24000 underrun!!! (at least 940.152 ms long) Status: state : XRUN trigger_time: 1252864095.582024000 tstamp : 0.000000 delay : 0 avail : 5499 avail_max : 31150 underrun!!! (at least 19.771 ms long) Status: state : XRUN trigger_time: 1252864096.537351000 tstamp : 0.000000 delay : 0 avail : 18760 avail_max : 30760 underrun!!! (at least 28.983 ms long) Status: state : XRUN trigger_time: 1252864096.570068000 tstamp : 0.000000 delay : 0 avail : 5499 avail_max : 24000 underrun!!! (at least 13.588 ms long) Status: state : XRUN trigger_time: 1252864096.612568000 tstamp : 0.000000 delay : 0 avail : 17499 avail_max : 24000 underrun!!! (at least 19.823 ms long) Status: state : XRUN trigger_time: 1252864096.639219000 tstamp : 0.000000 delay : 0 avail : 5499 avail_max : 24000 underrun!!! (at least 848.805 ms long) Status: state : XRUN trigger_time: 1252864096.672237000 tstamp : 0.000000 delay : 0 avail : 3014 avail_max : 34945 underrun!!! (at least 3.010 ms long) Status: state : XRUN trigger_time: 1252864097.541168000 tstamp : 0.000000 delay : 0 avail : 369 avail_max : 24000 underrun!!! (at least 18.652 ms long) Status: state : XRUN trigger_time: 1252864097.557743000 tstamp : 0.000000 delay : 0 avail : 18369 avail_max : 24369 underrun!!! (at least 548.891 ms long) Status: state : XRUN trigger_time: 1252864097.589739000 tstamp : 0.000000 delay : 0 avail : 18096 avail_max : 32584 underrun!!! (at least 45.578 ms long) Status: state : XRUN trigger_time: 1252864098.159709000 tstamp : 0.000000 delay : 0 avail : 19707 avail_max : 37707 underrun!!! (at least 37.704 ms long) Status: state : XRUN trigger_time: 1252864098.220655000 tstamp : 0.000000 delay : 0 avail : 369 avail_max : 24369
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