From: Russell King - ARM Linux <linux@armlinux.org.uk>
To: Romain Perier <romain.perier@collabora.com>
Cc: Archit Taneja <architt@codeaurora.org>,
David Airlie <airlied@linux.ie>, Heiko Stuebner <heiko@sntech.de>,
linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org,
linux-rockchip@lists.infradead.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] drm: dw_hdmi: Gate audio sampler clock from the enablement functions
Date: Fri, 10 Mar 2017 09:46:13 +0000 [thread overview]
Message-ID: <20170310094613.GQ21222@n2100.armlinux.org.uk> (raw)
In-Reply-To: <20170310093509.19044-1-romain.perier@collabora.com>
On Fri, Mar 10, 2017 at 10:35:09AM +0100, Romain Perier wrote:
> Currently, the audio sampler clock is enabled from dw_hdmi_setup() at
> step E. and is kept enabled for later use. This clock should be enabled
> and disabled along with the actual audio stream and not always on (that
> is bad for PM). Futhermore, this might cause sound glitches with some
> HDMI devices, as the CTS+N is forced to zero when the stream is disabled
> while the audio clock is still running.
>
> This commit adds a parameter to hdmi_audio_enable_clk() that controls
> when the audio sample clock must be enabled or disabled. Then, it moves
> the call to this function into dw_hdmi_audio_enable() and
> dw_hdmi_audio_disable().
How does this interact with the workaround given in my commit introducing
these functions? (Commit b90120a96608).
Setting N=0 is a work-around for iMX6, and we need the audio FIFO to be
loaded with data prior to setting N non-zero. If disabling the audio
clock prevents the audio FIFO being loaded, your patch will break iMX6.
--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
WARNING: multiple messages have this Message-ID (diff)
From: Russell King - ARM Linux <linux-I+IVW8TIWO2tmTQ+vhA3Yw@public.gmane.org>
To: Romain Perier <romain.perier-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org>
Cc: Archit Taneja <architt-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>,
Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>,
David Airlie <airlied-cv59FeDIM0c@public.gmane.org>,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org,
linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [PATCH] drm: dw_hdmi: Gate audio sampler clock from the enablement functions
Date: Fri, 10 Mar 2017 09:46:13 +0000 [thread overview]
Message-ID: <20170310094613.GQ21222@n2100.armlinux.org.uk> (raw)
In-Reply-To: <20170310093509.19044-1-romain.perier-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org>
On Fri, Mar 10, 2017 at 10:35:09AM +0100, Romain Perier wrote:
> Currently, the audio sampler clock is enabled from dw_hdmi_setup() at
> step E. and is kept enabled for later use. This clock should be enabled
> and disabled along with the actual audio stream and not always on (that
> is bad for PM). Futhermore, this might cause sound glitches with some
> HDMI devices, as the CTS+N is forced to zero when the stream is disabled
> while the audio clock is still running.
>
> This commit adds a parameter to hdmi_audio_enable_clk() that controls
> when the audio sample clock must be enabled or disabled. Then, it moves
> the call to this function into dw_hdmi_audio_enable() and
> dw_hdmi_audio_disable().
How does this interact with the workaround given in my commit introducing
these functions? (Commit b90120a96608).
Setting N=0 is a work-around for iMX6, and we need the audio FIFO to be
loaded with data prior to setting N non-zero. If disabling the audio
clock prevents the audio FIFO being loaded, your patch will break iMX6.
--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
WARNING: multiple messages have this Message-ID (diff)
From: linux@armlinux.org.uk (Russell King - ARM Linux)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] drm: dw_hdmi: Gate audio sampler clock from the enablement functions
Date: Fri, 10 Mar 2017 09:46:13 +0000 [thread overview]
Message-ID: <20170310094613.GQ21222@n2100.armlinux.org.uk> (raw)
In-Reply-To: <20170310093509.19044-1-romain.perier@collabora.com>
On Fri, Mar 10, 2017 at 10:35:09AM +0100, Romain Perier wrote:
> Currently, the audio sampler clock is enabled from dw_hdmi_setup() at
> step E. and is kept enabled for later use. This clock should be enabled
> and disabled along with the actual audio stream and not always on (that
> is bad for PM). Futhermore, this might cause sound glitches with some
> HDMI devices, as the CTS+N is forced to zero when the stream is disabled
> while the audio clock is still running.
>
> This commit adds a parameter to hdmi_audio_enable_clk() that controls
> when the audio sample clock must be enabled or disabled. Then, it moves
> the call to this function into dw_hdmi_audio_enable() and
> dw_hdmi_audio_disable().
How does this interact with the workaround given in my commit introducing
these functions? (Commit b90120a96608).
Setting N=0 is a work-around for iMX6, and we need the audio FIFO to be
loaded with data prior to setting N non-zero. If disabling the audio
clock prevents the audio FIFO being loaded, your patch will break iMX6.
--
RMK's Patch system: http://www.armlinux.org.uk/developer/patches/
FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up
according to speedtest.net.
next prev parent reply other threads:[~2017-03-10 9:47 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-10 9:35 [PATCH] drm: dw_hdmi: Gate audio sampler clock from the enablement functions Romain Perier
2017-03-10 9:35 ` Romain Perier
2017-03-10 9:35 ` Romain Perier
2017-03-10 9:46 ` Russell King - ARM Linux [this message]
2017-03-10 9:46 ` Russell King - ARM Linux
2017-03-10 9:46 ` Russell King - ARM Linux
2017-03-10 10:21 ` Romain Perier
2017-03-10 10:21 ` Romain Perier
2017-03-10 10:27 ` Russell King - ARM Linux
2017-03-10 10:27 ` Russell King - ARM Linux
2017-03-10 10:58 ` Romain Perier
2017-03-10 10:58 ` Romain Perier
2017-03-10 11:15 ` Russell King - ARM Linux
2017-03-10 11:15 ` Russell King - ARM Linux
2017-03-10 12:58 ` Romain Perier
2017-03-10 12:58 ` Romain Perier
2017-03-13 9:27 ` Neil Armstrong
2017-03-13 9:27 ` Neil Armstrong
2017-03-13 9:27 ` Neil Armstrong
2017-03-13 9:36 ` Russell King - ARM Linux
2017-03-13 9:36 ` Russell King - ARM Linux
2017-03-13 12:55 ` Jose Abreu
2017-03-13 12:55 ` Jose Abreu
2017-03-13 12:55 ` Jose Abreu
2017-03-13 13:10 ` Russell King - ARM Linux
2017-03-13 13:10 ` Russell King - ARM Linux
2017-03-13 18:49 ` Jose Abreu
2017-03-13 18:49 ` Jose Abreu
2017-03-13 18:49 ` Jose Abreu
2017-03-14 7:53 ` Romain Perier
2017-03-14 7:53 ` Romain Perier
2017-03-14 8:13 ` Neil Armstrong
2017-03-14 8:13 ` Neil Armstrong
2017-03-14 8:13 ` Neil Armstrong
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