From: Samuel Holland <samuel@sholland.org>
To: "Jernej Škrabec" <jernej.skrabec@siol.net>,
peron.clem@gmail.com, "Maxime Ripard" <mripard@kernel.org>,
"Chen-Yu Tsai" <wens@csie.org>, "Mark Brown" <broonie@kernel.org>,
"Liam Girdwood" <lgirdwood@gmail.com>
Cc: Rob Herring <robh+dt@kernel.org>,
Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
Marcus Cooper <codekipper@gmail.com>,
alsa-devel@alsa-project.org, devicetree@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-sunxi@googlegroups.com
Subject: Re: [linux-sunxi] [PATCH 05/16] ASoc: sun4i-i2s: Add 20 and 24 bit support
Date: Wed, 2 Sep 2020 21:22:33 -0500 [thread overview]
Message-ID: <fd714cb6-3650-1eb9-616d-33c00f1442eb@sholland.org> (raw)
In-Reply-To: <9148679.oVN3Z7rve9@kista>
On 9/2/20 1:10 PM, Jernej Škrabec wrote:
> Hi Samuel!
>
> Dne petek, 10. julij 2020 ob 07:44:51 CEST je Samuel Holland napisal(a):
>> On 7/4/20 6:38 AM, Clément Péron wrote:
>>> From: Marcus Cooper <codekipper@gmail.com>
>>>
>>> Extend the functionality of the driver to include support of 20 and
>>> 24 bits per sample.
>>>
>>> Signed-off-by: Marcus Cooper <codekipper@gmail.com>
>>> Signed-off-by: Clément Péron <peron.clem@gmail.com>
>>> ---
>>>
>>> sound/soc/sunxi/sun4i-i2s.c | 11 +++++++++--
>>> 1 file changed, 9 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/sound/soc/sunxi/sun4i-i2s.c b/sound/soc/sunxi/sun4i-i2s.c
>>> index f78167e152ce..bc7f9343bc7a 100644
>>> --- a/sound/soc/sunxi/sun4i-i2s.c
>>> +++ b/sound/soc/sunxi/sun4i-i2s.c
>>> @@ -577,6 +577,9 @@ static int sun4i_i2s_hw_params(struct
>>> snd_pcm_substream *substream,>
>>> case 16:
>>> width = DMA_SLAVE_BUSWIDTH_2_BYTES;
>>> break;
>>>
>>> + case 32:
>>> + width = DMA_SLAVE_BUSWIDTH_4_BYTES;
>>> + break;
>>
>> This breaks the sun4i variants, because sun4i_i2s_get_wss returns 4 for a 32
>> bit width, but it needs to return 3.
>
> I'm not sure what has WSS with physical width and DMA?
This is the change where creating a S24_LE stream no longer fails with -EINVAL.
So this is the change where userspace stops downsampling 24-bit audio sources.
So this is the change where playback of 24-bit audio sources breaks, because WSS
is programmed wrong.
>> As a side note, I wonder why we use the physical width (the spacing between
>> samples in RAM) to drive the slot width. S24_LE takes up 4 bytes per sample
>> in RAM, which we need for DMA. But I don't see why we would want to
>> transmit the padding over the wire. I would expect it to be transmitted the
>> same as S24_3LE (which has no padding). It did not matter before, because
>> the only supported format had no padding.
>
> Allwinner DMA engines support only 1, 2, 4 and sometimes 8 bytes for bus
> width, so if sample is 24 bits in size, we have no other way but to transmit
> padding too.
I understand why we do 4 byte DMA from RAM <=> I2S FIFO; that was not my
question. I'm referring to the actual wire format (FIFO <=> PCM_DIN/DOUT). The
sample is already truncated from 32 bits to 24 bits in the FIFO -- that's what
TXIM and RXOM in FIFO_CTRL control.
If a sample is 24 bits wide, why would we send 32 BCLKs for every LRCK? I would
expect the slot width to match the sample resolution by default. But yet we have
this code in the driver:
unsigned int word_size = params_width(params);
unsigned int slot_width = params_physical_width(params);
I think slot_width should be the same as word_size, and I suggest changing it
before adding 20/24-bit support.
> Best regards,
> Jernej
Regards,
Samuel
>>> default:
>>> dev_err(dai->dev, "Unsupported physical sample width:
> %d\n",
>>>
>>> params_physical_width(params));
>>>
>>> @@ -1063,6 +1066,10 @@ static int sun4i_i2s_dai_probe(struct snd_soc_dai
>>> *dai)>
>>> return 0;
>>>
>>> }
>>>
>>> +#define SUN4I_FORMATS (SNDRV_PCM_FMTBIT_S16_LE | \
>>> + SNDRV_PCM_FMTBIT_S20_LE | \
>>> + SNDRV_PCM_FMTBIT_S24_LE)
>>> +
>>>
>>> static struct snd_soc_dai_driver sun4i_i2s_dai = {
>>>
>>> .probe = sun4i_i2s_dai_probe,
>>> .capture = {
>>>
>>> @@ -1070,14 +1077,14 @@ static struct snd_soc_dai_driver sun4i_i2s_dai = {
>>>
>>> .channels_min = 1,
>>> .channels_max = 8,
>>> .rates = SNDRV_PCM_RATE_8000_192000,
>>>
>>> - .formats = SNDRV_PCM_FMTBIT_S16_LE,
>>> + .formats = SUN4I_FORMATS,
>>>
>>> },
>>> .playback = {
>>>
>>> .stream_name = "Playback",
>>> .channels_min = 1,
>>> .channels_max = 8,
>>> .rates = SNDRV_PCM_RATE_8000_192000,
>>>
>>> - .formats = SNDRV_PCM_FMTBIT_S16_LE,
>>> + .formats = SUN4I_FORMATS,
>>>
>>> },
>>> .ops = &sun4i_i2s_dai_ops,
>>> .symmetric_rates = 1,
>
>
>
>
next prev parent reply other threads:[~2020-09-03 2:22 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-04 11:38 [PATCH 00/16] Add Allwinner H3/H5/H6/A64 HDMI audio Clément Péron
2020-07-04 11:38 ` [PATCH 01/16] ASoC: sun4i-i2s: Add support for H6 I2S Clément Péron
2020-07-06 5:15 ` Maxime Ripard
2020-07-10 5:44 ` [linux-sunxi] " Samuel Holland
2020-07-10 19:22 ` Jernej Škrabec
2020-07-11 1:43 ` Samuel Holland
2020-07-22 8:56 ` Clément Péron
2020-07-04 11:38 ` [PATCH 02/16] ASoC: sun4i-i2s: Adjust LRCLK width Clément Péron
2020-07-10 5:44 ` [linux-sunxi] " Samuel Holland
2020-07-04 11:38 ` [PATCH 03/16] dt-bindings: ASoC: sun4i-i2s: Add H6 compatible Clément Péron
2020-07-04 11:38 ` [PATCH 04/16] ASoC: sun4i-i2s: Set sign extend sample Clément Péron
2020-07-06 5:17 ` Maxime Ripard
2020-07-10 5:44 ` [linux-sunxi] " Samuel Holland
2020-07-22 9:12 ` Clément Péron
2020-07-04 11:38 ` [PATCH 05/16] ASoc: sun4i-i2s: Add 20 and 24 bit support Clément Péron
2020-07-06 5:18 ` Maxime Ripard
2020-07-10 5:44 ` [linux-sunxi] " Samuel Holland
2020-09-02 18:10 ` Jernej Škrabec
2020-09-03 2:22 ` Samuel Holland [this message]
2020-09-03 7:40 ` Maxime Ripard
2020-09-04 16:16 ` Charles Keepax
2020-09-04 16:23 ` Mark Brown
2020-07-04 11:38 ` [PATCH 06/16] ASoC: sun4i-i2s: Adjust regmap settings Clément Péron
2020-07-06 5:24 ` Maxime Ripard
2020-07-04 11:38 ` [PATCH 07/16] ASoC: sun4i-i2s: Fix sun8i volatile regs Clément Péron
2020-07-06 5:25 ` Maxime Ripard
2020-07-04 11:38 ` [PATCH 08/16] arm64: dts: allwinner: h6: Add HDMI audio node Clément Péron
2020-07-06 5:29 ` Maxime Ripard
2020-07-08 16:17 ` Jernej Škrabec
2020-07-04 11:38 ` [PATCH 09/16] arm64: dts: allwinner: h6: Enable HDMI sound for Beelink GS1 Clément Péron
2020-07-04 11:38 ` [PATCH 10/16] arm: dts: sunxi: h3/h5: Add DAI node for HDMI Clément Péron
2020-07-18 21:24 ` [linux-sunxi] " Samuel Holland
2020-07-04 11:38 ` [PATCH 11/16] arm: dts: sunxi: h3/h5: Add HDMI audio Clément Péron
2020-07-04 11:38 ` [PATCH 12/16] arm64: dts: allwinner: a64: Add DAI node for HDMI Clément Péron
2020-07-04 11:38 ` [PATCH 13/16] arm64: dts: allwinner: a64: Add HDMI audio Clément Péron
2020-07-06 5:31 ` Maxime Ripard
2020-07-08 16:00 ` Jernej Škrabec
2020-07-04 11:39 ` [PATCH 14/16] arm: sun8i: h3: Add HDMI audio to Orange Pi 2 Clément Péron
2020-07-04 11:39 ` [PATCH 15/16] arm: sun8i: h3: Add HDMI audio to Beelink X2 Clément Péron
2020-07-04 11:39 ` [PATCH 16/16] arm64: dts: allwinner: a64: Add HDMI audio to Pine64 Clément Péron
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