From: Jarkko Nikula <jhnikula@gmail.com>
To: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Cc: "tiwai@suse.de" <tiwai@suse.de>,
"alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
"broonie@opensource.wolfsonmicro.com"
<broonie@opensource.wolfsonmicro.com>,
"Nurkkala Eero.An (EXT-Offcode/Oulu)"
<ext-Eero.Nurkkala@nokia.com>,
"lrg@slimlogic.co.uk" <lrg@slimlogic.co.uk>
Subject: Re: [RFC 3/4] OMAP3: McBSP: Add interface for transmit FIFO state query
Date: Wed, 3 Mar 2010 16:18:42 +0200 [thread overview]
Message-ID: <20100303161842.7b82ea8c.jhnikula@gmail.com> (raw)
In-Reply-To: <201003031202.48598.peter.ujfalusi@nokia.com>
On Wed, 3 Mar 2010 12:02:48 +0200
Peter Ujfalusi <peter.ujfalusi@nokia.com> wrote:
> The command for test:
> aplay -fdat -d 1 /dev/urandom
>
I recommend to use /dev/zero instead since urandom takes CPU time.
> [ 96.290924] XBUFFSTAT: 0
> [ 96.293487] XBUFFSTAT: 0
> [ 96.296020] XBUFFSTAT: 0
> [ 96.299774] XBUFFSTAT: 1
>
> So the buffer is kept full in element mode, as it is expected.
>
I was expecting to see more variations. IRCC, the DMA in OMAP is doing
transfers over the memory bus using some small bursts but I'm not
completely sure. I'm thinking if that could explain the Eero's and
Liam's observations?
> So according to XBUFSTAT we have played out 289 samples.
> based on the time we actually played 288.528 samples.
>
> I would say this is really close to what we would expect to have?
>
Sounds accurate enough.
> Note: I have used printk for these, which pretty much alters the behavior a bit
> in timing wise...
>
BTW: There is OMAP3 port in LTTng.
--
Jarkko
next prev parent reply other threads:[~2010-03-03 14:17 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-02 13:39 [RFC 0/4] FIFO caused playback delay (latency) handling in soc Peter Ujfalusi
2010-03-02 13:39 ` [RFC 1/4] ASoC: core: soc level wrapper for pcm_pointer callback Peter Ujfalusi
2010-03-02 13:39 ` [RFC 2/4] ASoC: core: Add delay operation to snd_soc_dai_ops Peter Ujfalusi
2010-03-02 13:45 ` Mark Brown
2010-03-02 13:49 ` Peter Ujfalusi
2010-03-02 13:54 ` Mark Brown
2010-03-02 13:39 ` [RFC 3/4] OMAP3: McBSP: Add interface for transmit FIFO state query Peter Ujfalusi
2010-03-02 13:45 ` Mark Brown
2010-03-02 13:52 ` Eero Nurkkala
2010-03-02 13:58 ` Liam Girdwood
2010-03-02 14:02 ` Peter Ujfalusi
2010-03-02 14:06 ` Jarkko Nikula
2010-03-03 6:07 ` Eero Nurkkala
2010-03-03 7:03 ` Jarkko Nikula
2010-03-03 10:02 ` Peter Ujfalusi
2010-03-03 10:07 ` Peter Ujfalusi
2010-03-03 14:18 ` Jarkko Nikula [this message]
2010-03-03 15:01 ` Peter Ujfalusi
2010-03-04 7:30 ` Peter Ujfalusi
2010-03-03 19:00 ` ext-Eero.Nurkkala
2010-03-03 19:07 ` ext-Eero.Nurkkala
2010-03-04 7:53 ` Peter Ujfalusi
2010-03-04 8:09 ` Peter Ujfalusi
2010-03-04 8:46 ` Eero Nurkkala
2010-03-02 13:39 ` [RFC 4/4] ASoC: OMAP3: Report delay on playback caused by the internal FIFO Peter Ujfalusi
2010-03-02 13:47 ` Mark Brown
2010-03-02 13:52 ` Peter Ujfalusi
2010-03-02 14:06 ` Mark Brown
2010-03-02 13:53 ` [RFC 0/4] FIFO caused playback delay (latency) handling in soc Mark Brown
2010-03-02 23:29 ` Raymond Yau
2010-03-03 10:03 ` Mark Brown
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