From: Jose Abreu <Jose.Abreu-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>
To: Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Jose Abreu <Jose.Abreu-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>
Cc: alsa-devel-K7yf7f+aM1XWsZ/bQMPhNw@public.gmane.org,
Carlos Palminha
<CARLOS.PALMINHA-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>,
Liam Girdwood <lgirdwood-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Jaroslav Kysela <perex-/Fr2/VpizcU@public.gmane.org>,
Takashi Iwai <tiwai-IBi9RG/b67k@public.gmane.org>,
Rob Herring <robh-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Alexey Brodkin
<Alexey.Brodkin-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>,
linux-snps-arc-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH 3/4 v7] ASoC: dwc: Add PIO PCM extension
Date: Wed, 25 May 2016 11:11:47 +0100 [thread overview]
Message-ID: <57457A63.5060702@synopsys.com> (raw)
In-Reply-To: <20160524175144.GO8206-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
Hi Mark,
On 24-05-2016 18:51, Mark Brown wrote:
> On Tue, May 24, 2016 at 06:07:14PM +0100, Jose Abreu wrote:
>> On 24-05-2016 17:41, Mark Brown wrote:
> Please fix your mail client to word wrap within paragraphs at something
> substantially less than 80 columns. Doing this makes your messages much
> easier to read and reply to.
>
>>>> if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
>>>> i2s_write_reg(dev->i2s_base, ITER, 1);
>>> That seems wrong, or at least something that should be separate?
>>> Previously we needed interrupts for DMA operation but now we enable
>>> interrupts only if we don't use DMA. It feels like we want to make the
>>> change for DMA separately if only to make it clear for bisection, are we
>>> 100% sure that masking the interrupt won't also mask the DMA request
>>> signals?
>> Indeed I thought about this and the interrupts must also be enabled when in DMA
>> mode. Although there is no interrupt handler in the original driver (without
>> this patches) in some setups the interrupt line may be connected to the DMA
>> controller. I will drop this change and always enable interrupts. Please note
>> that I don't have a setup with DMA support so I can only test using the PIO mode.
> Presumably you can talk to your hardware colleagues and get them to make
> you a FPGA with a DMA IP available?
Its already in the todo list.
>
>>> This also seems wrong. We're forcing PIO if an interrupt is provided
>>> rather than based on DMA being configured which means that if the
>>> interrupt is wired up and happens to be described in DT we'll get worse
>> How should I then determine which mode to use?
>> - Check if DMA parameters are declared in DT, or
>> - Check if snd_dmaengine_pcm_register() fails, or
>> - Assume PIO mode will be used when compiling with PIO PCM, or
>> - Something else ?
> You could either unconditionally register the PIO driver and only
> actually start using it if the driver is instantiated or you could check
> to see if the registration function works (handling deferred probe - if
> the DMA driver just didn't load yet you should wait for it).
I think I will take the second option. Something like this:
"
ret = snd_dmaengine_pcm_register(...)
if (ret == -EPROBE_DEFER)
return ret;
else
pio_register(...);
"?
Best regards,
Jose Miguel Abreu
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next prev parent reply other threads:[~2016-05-25 10:11 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-23 10:02 [PATCH 0/4 v7] Add I2S audio support for ARC AXS10x boards Jose Abreu
2016-05-23 10:02 ` [PATCH 1/4 v7] ASoC: dwc: Add helper functions to disable/enable irqs Jose Abreu
2016-05-23 17:50 ` Applied "ASoC: dwc: Add helper functions to disable/enable irqs" to the asoc tree Mark Brown
2016-05-23 10:02 ` [PATCH 2/4 v7] ASoC: dwc: Do not use devm_clk_get() if using platform data Jose Abreu
2016-05-23 16:57 ` Mark Brown
2016-05-23 10:02 ` [PATCH 3/4 v7] ASoC: dwc: Add PIO PCM extension Jose Abreu
2016-05-24 16:41 ` Mark Brown
2016-05-24 17:07 ` Jose Abreu
2016-05-24 17:51 ` Mark Brown
[not found] ` <20160524175144.GO8206-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
2016-05-25 10:11 ` Jose Abreu [this message]
2016-05-25 10:18 ` Mark Brown
2016-05-25 10:49 ` Jose Abreu
[not found] ` <57458328.8080900-HKixBCOQz3hWk0Htik3J/w@public.gmane.org>
2016-05-25 13:41 ` Mark Brown
2016-05-23 10:02 ` [PATCH 4/4 v7] ASoC: dwc: Add irq parameter to DOCUMENTATION Jose Abreu
2016-05-23 21:31 ` Rob Herring
2016-06-13 16:54 ` Applied "ASoC: dwc: Add irq parameter to DOCUMENTATION" to the asoc tree Mark Brown
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