Message-ID: <54476640.5050603@atmel.com>
Date: Wed, 22 Oct 2014 16:09:36 +0800
From: Bo Shen <voice.shen@atmel.com>
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To: Peter Rosin <peda@axentia.se>
CC: "'alsa-devel@alsa-project.org'" <alsa-devel@alsa-project.org>,
        "Takashi Iwai" <tiwai@suse.de>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Liam Girdwood <lgirdwood@gmail.com>, "Mark Brown" <broonie@kernel.org>
Subject: Re: [alsa-devel] [PATCH] ASoC: atmel_ssc_dai: Track playback and
 capture CMR dividers separately.
References: <a541333cf46b4c61b790df927d4b315d@EMAIL.axentia.se> <5445BCBF.5090002@atmel.com> <dc4461593ddb4d539f2db74b69bab98c@EMAIL.axentia.se> <544620C8.4040001@atmel.com> <8559eca320324092be82f7d942606102@EMAIL.axentia.se> <544707F3.1020505@atmel.com> <c61abc1ef0f341c2be04e3d7b07d97de@EMAIL.axentia.se>
In-Reply-To: <c61abc1ef0f341c2be04e3d7b07d97de@EMAIL.axentia.se>
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Sender: linux-kernel-owner@vger.kernel.org

Hi Peter,

On 10/22/2014 12:47 PM, Peter Rosin wrote:
> Hi!
>
>> Hi Peter,
>>
>> On 10/21/2014 09:05 PM, Peter Rosin wrote:
>>> I did some further tests, and the following program fails without the patch:
>>
>> With the patch, it is OK?
>
> Yes.
>
>>> #include <sys/ioctl.h>
>>> #include <unistd.h>
>>> #include <fcntl.h>
>>> #include <sys/soundcard.h>
>>>
>>> int
>>> main(void)
>>> {
>>> 	int fd;
>>> 	int format;
>>> 	int channels;
>>>
>>> 	if ((fd = open("/dev/dsp", O_WRONLY, 0)) == -1) {
>>> 		perror("open");
>>> 		return 1;
>>> 	}
>>> 	format = AFMT_S16_LE;
>>> 	if (ioctl(fd, SNDCTL_DSP_SETFMT, &format) == -1) {
>>> 		perror("SNDCTL_DSP_SETFMT");
>>> 		return 1;
>>> 	}
>>> 	channels = 2;
>>> 	if (ioctl(fd, SNDCTL_DSP_CHANNELS, &channels) == -1) {
>>> 		perror("SNDCTL_DSP_CHANNELS");
>>> 		return 1;
>>> 	}
>>> 	return 0;
>>> }
>>>
>>> Output:
>>> SNDCTL_DSP_CHANNELS: Device or resource busy
>>
>> This return from codec or from atmel_ssc_dai?
>
> This -EBUSY definitely comes from atmel_ssc_set_dai_sysclk, when my
> card-driver tries to set ATMEL_SSC_CMR_DIV. With the patch, it works.
> (the codec is spdif-transmitter, since the i2c interface of the actual tfa9879
> codec is not directly reachable from the linux cpu, but that has nothing to
> do with this issue).

I try to reproduce it (using the code your pasted directly) on atmel 
sama5d3xek with wm8904 code, don't meet this error.

I also go through the OSS code, I still don't find this is related with 
atmel_ssc_set_dai_sysclk.

So, am I missing something or something else?

>>> (I admin to having edited the above code slightly in this mail, so I
> s/admin/admit/
>>> might have introduced some silly bug, but you get what I mean, just
>>> open the device and request some parameters, and boom: -EBUSY)
>
> Cheers,
> Peter
>

Best Regards,
Bo Shen
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