From: Liam Girdwood <lrg@slimlogic.co.uk>
To: ext-eero.nurkkala@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>,
"Ujfalusi Peter (Nokia-D/Tampere)" <peter.ujfalusi@nokia.com>
Subject: Re: [RFC 3/4] OMAP3: McBSP: Add interface for transmit FIFO state query
Date: Tue, 02 Mar 2010 13:58:04 +0000 [thread overview]
Message-ID: <1267538284.3201.15.camel@odin> (raw)
In-Reply-To: <1267537920.24345.7.camel@eenurkka-desktop>
On Tue, 2010-03-02 at 15:52 +0200, Eero Nurkkala wrote:
> On Tue, 2010-03-02 at 14:39 +0100, Ujfalusi Peter (Nokia-D/Tampere)
> wrote:
> > New function for reading the XBUFFSTAT register, which holds
> > the fill state of the transmit buffer on McBSP.
> >
> > Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
> > ---
>
> Reading the XBUFFSTAT register is by no means accurate.
> IIRC, it reports the buffer status incorrectly about 1/50 times
> on average (@ 48000khz); with simple math, it may be read during the DMA
> burst. Or is it guaranteed not being read during DMA transfer / have
> you otherwise verified the behavior?
I agree, I've also seen XBUFFSTAT giving complete garbage with mcbsp3.
Liam
--
Freelance Developer, SlimLogic Ltd
ASoC and Voltage Regulator Maintainer.
http://www.slimlogic.co.uk
next prev parent reply other threads:[~2010-03-02 13:58 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 [this message]
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
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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