From: Lars-Peter Clausen <lars@metafoo.de>
To: Russell King - ARM Linux <linux@arm.linux.org.uk>,
Anssi Hannula <anssi.hannula@iki.fi>,
Takashi Iwai <tiwai@suse.de>
Cc: Fabio Estevam <fabio.estevam@freescale.com>,
alsa-devel@alsa-project.org, dri-devel@lists.freedesktop.org,
Mark Brown <broonie@kernel.org>, Yakir Yang <ykk@rock-chips.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH RFC v2 10/13] sound/core: add DRM ELD helper
Date: Thu, 07 May 2015 13:11:16 +0200 [thread overview]
Message-ID: <554B4854.7090209@metafoo.de> (raw)
In-Reply-To: <20150507104102.GA2067@n2100.arm.linux.org.uk>
On 05/07/2015 12:41 PM, Russell King - ARM Linux wrote:
[...]
>>> What I'm concerned about is that when the ALSA parameter refining
>>> starts, we start with (eg) 2-8 channels, 32-192kHz. Given that,
>>> if we invoke the channel restriction before the rate restriction,
>>> we would end up limiting to 2 channel at 32-192kHz. If we apply
>>> the restrictions in the opposite order, we'd restrict to 6
>>> channel, 32-48kHz. Neither are obviously correct in this
>>> circumstance, and I don't really see a way to solve it given my
>>> understanding of the way ALSA's parameter refinement works.
>>>
>>> I suspect this is why most HDMI drivers are implemented such that
>>> they take the maximum capabilities over all SADs, which would end
>>> up restricting audio in the above case to: up to 6 channels, at
>>> 32, 44.1, 48, 96 and 192kHz, even though 6 channel @ 192kHz isn't
>>> hasn't been indicated as supported.
>>>
>>> Most of this is speculation though, based off what is in the
>>> documentation. As I say, I don't have enough real-world examples
>>> to get a feel for what manufacturers _actually_ do to give a hint
>>> as to how the documentation should be interpreted.
>
> ... so this is probably less than speculation.
>
> So, ALSA gurus, how do we handle this? How do we arrange the parameter
> resolution such that ALSA can permit _either_ 2 channels at 192kHz or 6
> channels at 48kHz, but not 6 channels at 192kHz? Right now, I don't
> see how that's possible.
That's pretty straight forward and can be done using custom rules linking
the number of channels to the sample rate. Have a look at
snd_ac97_pcm_double_rate_rules() this is pretty much the same constraint.
- Lars
WARNING: multiple messages have this Message-ID (diff)
From: lars@metafoo.de (Lars-Peter Clausen)
To: linux-arm-kernel@lists.infradead.org
Subject: [alsa-devel] [PATCH RFC v2 10/13] sound/core: add DRM ELD helper
Date: Thu, 07 May 2015 13:11:16 +0200 [thread overview]
Message-ID: <554B4854.7090209@metafoo.de> (raw)
In-Reply-To: <20150507104102.GA2067@n2100.arm.linux.org.uk>
On 05/07/2015 12:41 PM, Russell King - ARM Linux wrote:
[...]
>>> What I'm concerned about is that when the ALSA parameter refining
>>> starts, we start with (eg) 2-8 channels, 32-192kHz. Given that,
>>> if we invoke the channel restriction before the rate restriction,
>>> we would end up limiting to 2 channel at 32-192kHz. If we apply
>>> the restrictions in the opposite order, we'd restrict to 6
>>> channel, 32-48kHz. Neither are obviously correct in this
>>> circumstance, and I don't really see a way to solve it given my
>>> understanding of the way ALSA's parameter refinement works.
>>>
>>> I suspect this is why most HDMI drivers are implemented such that
>>> they take the maximum capabilities over all SADs, which would end
>>> up restricting audio in the above case to: up to 6 channels, at
>>> 32, 44.1, 48, 96 and 192kHz, even though 6 channel @ 192kHz isn't
>>> hasn't been indicated as supported.
>>>
>>> Most of this is speculation though, based off what is in the
>>> documentation. As I say, I don't have enough real-world examples
>>> to get a feel for what manufacturers _actually_ do to give a hint
>>> as to how the documentation should be interpreted.
>
> ... so this is probably less than speculation.
>
> So, ALSA gurus, how do we handle this? How do we arrange the parameter
> resolution such that ALSA can permit _either_ 2 channels at 192kHz or 6
> channels at 48kHz, but not 6 channels at 192kHz? Right now, I don't
> see how that's possible.
That's pretty straight forward and can be done using custom rules linking
the number of channels to the sample rate. Have a look at
snd_ac97_pcm_double_rate_rules() this is pretty much the same constraint.
- Lars
next prev parent reply other threads:[~2015-05-07 11:11 UTC|newest]
Thread overview: 148+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-02 9:20 [RFC v2 0/13] dw_hdmi cleanups, audio preparation, helpers and ahb audio support Russell King - ARM Linux
2015-04-02 9:20 ` Russell King - ARM Linux
2015-04-02 9:21 ` [PATCH RFC v2 01/13] drm: imx/dw_hdmi: move phy comments Russell King
2015-04-02 9:21 ` Russell King
2015-04-02 9:21 ` [PATCH RFC v2 02/13] drm: bridge/dw_hdmi: clean up phy configuration Russell King
2015-04-02 9:21 ` Russell King
2015-04-02 9:21 ` [PATCH RFC v2 03/13] drm: bridge/dw_hdmi: clean up hdmi_set_clk_regenerator() Russell King
2015-04-02 9:21 ` Russell King
2015-04-02 9:21 ` [PATCH RFC v2 04/13] drm: bridge/dw_hdmi: use drm_hdmi_avi_infoframe_from_display_mode() Russell King
2015-04-02 9:21 ` Russell King
2015-04-02 9:21 ` [PATCH RFC v2 05/13] drm: bridge/dw_hdmi: simplify hdmi_config_AVI() a little Russell King
2015-04-02 9:21 ` Russell King
2015-04-02 9:21 ` [PATCH RFC v2 06/13] drm: bridge/dw_hdmi: remove mhsyncpolarity/mvsyncpolarity/minterlaced Russell King
2015-04-02 9:21 ` Russell King
2015-04-02 9:21 ` [PATCH RFC v2 07/13] drm: bridge/dw_hdmi: introduce interface to setting sample rate Russell King
2015-04-02 9:21 ` Russell King
2015-04-02 9:21 ` [PATCH RFC v2 08/13] drm: bridge/dw_hdmi: introduce interfaces to enable and disable audio Russell King
2015-04-02 9:21 ` Russell King
2015-04-02 9:22 ` [PATCH RFC v2 09/13] drm/edid: add function to help find SADs Russell King
2015-04-02 9:22 ` Russell King
2015-04-02 9:22 ` [PATCH RFC v2 10/13] sound/core: add DRM ELD helper Russell King
2015-04-02 9:22 ` Russell King
2015-04-05 15:57 ` Takashi Iwai
2015-04-05 15:57 ` Takashi Iwai
2015-04-05 16:20 ` Russell King - ARM Linux
2015-04-05 16:20 ` Russell King - ARM Linux
2015-04-05 16:46 ` Takashi Iwai
2015-04-05 16:46 ` Takashi Iwai
2015-04-05 17:26 ` Russell King - ARM Linux
2015-04-05 17:26 ` Russell King - ARM Linux
2015-05-06 17:02 ` Anssi Hannula
2015-05-06 17:02 ` Anssi Hannula
2015-05-07 10:41 ` Russell King - ARM Linux
2015-05-07 10:41 ` Russell King - ARM Linux
2015-05-07 11:11 ` Lars-Peter Clausen [this message]
2015-05-07 11:11 ` [alsa-devel] " Lars-Peter Clausen
2015-05-08 10:56 ` Jyri Sarha
2015-05-08 10:56 ` Jyri Sarha
2015-05-08 11:42 ` Russell King - ARM Linux
2015-05-08 11:42 ` Russell King - ARM Linux
2015-05-05 22:35 ` Mark Brown
2015-05-05 22:35 ` Mark Brown
2015-05-06 8:58 ` Liam Girdwood
2015-05-06 8:58 ` [alsa-devel] " Liam Girdwood
2015-05-08 13:16 ` Jyri Sarha
2015-05-08 13:16 ` Jyri Sarha
2015-05-08 13:27 ` Russell King - ARM Linux
2015-05-08 13:27 ` Russell King - ARM Linux
2015-05-08 13:37 ` Jyri Sarha
2015-05-08 13:37 ` [alsa-devel] " Jyri Sarha
2015-04-02 9:22 ` [PATCH RFC v2 11/13] sound/core: add IEC958 channel status helper Russell King
2015-04-02 9:22 ` Russell King
2015-04-02 9:22 ` [PATCH RFC v2 12/13] drm: bridge/dw_hdmi-ahb-audio: add audio driver Russell King
2015-04-02 9:22 ` Russell King
2015-04-02 9:22 ` [PATCH RFC v2 13/13] drm: bridge/dw_hdmi-ahb-audio: parse ELD from HDMI driver Russell King
2015-04-02 9:22 ` Russell King
2015-05-09 10:25 ` [PATCH v3 0/13] dw_hdmi cleanups, audio preparation, helpers and ahb audio support Russell King - ARM Linux
2015-05-09 10:25 ` Russell King - ARM Linux
2015-05-09 10:25 ` [PATCH 01/13] drm: imx/dw_hdmi: move phy comments Russell King
2015-05-09 10:25 ` Russell King
2015-05-09 10:26 ` [PATCH 02/13] drm: bridge/dw_hdmi: clean up phy configuration Russell King
2015-05-09 10:26 ` Russell King
2015-05-22 15:19 ` Yakir
2015-05-22 15:19 ` Yakir
2015-05-09 10:26 ` [PATCH 03/13] drm: bridge/dw_hdmi: clean up hdmi_set_clk_regenerator() Russell King
2015-05-09 10:26 ` Russell King
2015-05-22 15:22 ` Yakir
2015-05-22 15:22 ` Yakir
2015-05-09 10:26 ` [PATCH 04/13] drm: bridge/dw_hdmi: use drm_hdmi_avi_infoframe_from_display_mode() Russell King
2015-05-09 10:26 ` Russell King
2015-05-09 10:26 ` [PATCH 05/13] drm: bridge/dw_hdmi: simplify hdmi_config_AVI() a little Russell King
2015-05-09 10:26 ` Russell King
2015-05-09 10:26 ` [PATCH 06/13] drm: bridge/dw_hdmi: remove mhsyncpolarity/mvsyncpolarity/minterlaced Russell King
2015-05-09 10:26 ` Russell King
2015-05-09 10:26 ` [PATCH 07/13] drm: bridge/dw_hdmi: introduce interface to setting sample rate Russell King
2015-05-09 10:26 ` Russell King
2015-05-22 15:26 ` Yakir
2015-05-22 15:26 ` Yakir
2015-05-09 10:26 ` [PATCH 08/13] drm: bridge/dw_hdmi: introduce interfaces to enable and disable audio Russell King
2015-05-09 10:26 ` Russell King
2015-05-22 15:28 ` Yakir
2015-05-22 15:28 ` Yakir
2015-05-09 10:26 ` [PATCH 09/13] drm/edid: add function to help find SADs Russell King
2015-05-09 10:26 ` Russell King
2015-05-09 10:26 ` [PATCH 10/13] sound/core: add DRM ELD helper Russell King
2015-05-09 10:26 ` Russell King
2015-05-22 12:20 ` [alsa-devel] " Mark Brown
2015-05-22 12:20 ` Mark Brown
2015-05-22 13:15 ` Russell King - ARM Linux
2015-05-22 13:15 ` Russell King - ARM Linux
2015-05-22 13:30 ` Takashi Iwai
2015-05-22 13:30 ` Takashi Iwai
2015-05-22 13:53 ` Russell King - ARM Linux
2015-05-22 13:53 ` Russell King - ARM Linux
2015-05-22 13:54 ` Takashi Iwai
2015-05-22 13:54 ` Takashi Iwai
2015-05-22 14:00 ` Russell King - ARM Linux
2015-05-22 14:00 ` Russell King - ARM Linux
2015-05-22 14:02 ` Takashi Iwai
2015-05-22 14:02 ` Takashi Iwai
2015-05-22 14:05 ` Takashi Iwai
2015-05-22 14:05 ` Takashi Iwai
2015-05-22 16:12 ` Russell King - ARM Linux
2015-05-22 16:12 ` Russell King - ARM Linux
2015-05-09 10:26 ` [PATCH 11/13] sound/core: add IEC958 channel status helper Russell King
2015-05-09 10:26 ` Russell King
2015-05-22 12:40 ` Mark Brown
2015-05-22 12:40 ` Mark Brown
2015-05-09 10:26 ` [PATCH 12/13] drm: bridge/dw_hdmi-ahb-audio: add audio driver Russell King
2015-05-09 10:26 ` Russell King
2015-05-09 16:49 ` [alsa-devel] " Anssi Hannula
2015-05-09 16:49 ` Anssi Hannula
2015-05-09 16:55 ` Russell King - ARM Linux
2015-05-09 16:55 ` Russell King - ARM Linux
2015-05-09 17:07 ` Anssi Hannula
2015-05-09 17:07 ` Anssi Hannula
2015-05-09 17:40 ` Russell King - ARM Linux
2015-05-09 17:40 ` Russell King - ARM Linux
2015-05-09 17:53 ` Russell King - ARM Linux
2015-05-09 17:53 ` Russell King - ARM Linux
2015-05-09 17:55 ` Anssi Hannula
2015-05-09 17:55 ` Anssi Hannula
2015-05-09 18:11 ` Russell King - ARM Linux
2015-05-09 18:11 ` Russell King - ARM Linux
2015-05-10 18:59 ` Anssi Hannula
2015-05-10 18:59 ` Anssi Hannula
2015-05-10 19:33 ` Russell King - ARM Linux
2015-05-10 19:33 ` Russell King - ARM Linux
2015-05-10 20:47 ` Anssi Hannula
2015-05-10 20:47 ` Anssi Hannula
2015-05-11 15:58 ` Mark Brown
2015-05-11 15:58 ` [alsa-devel] " Mark Brown
2015-05-09 10:26 ` [PATCH 13/13] drm: bridge/dw_hdmi-ahb-audio: parse ELD from HDMI driver Russell King
2015-05-09 10:26 ` Russell King
2015-05-27 10:43 ` Daniel Vetter
2015-05-27 10:43 ` Daniel Vetter
2015-05-27 11:43 ` Mark Brown
2015-05-27 11:43 ` Mark Brown
2015-05-27 17:31 ` Russell King - ARM Linux
2015-05-27 17:31 ` Russell King - ARM Linux
2015-05-27 21:29 ` Daniel Vetter
2015-05-27 21:29 ` Daniel Vetter
2015-05-27 21:44 ` Russell King - ARM Linux
2015-05-27 21:44 ` Russell King - ARM Linux
2015-05-28 6:43 ` Daniel Vetter
2015-05-28 6:43 ` Daniel Vetter
2015-05-28 4:56 ` [alsa-devel] " Takashi Iwai
2015-05-28 4:56 ` Takashi Iwai
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