linux-kernel - Re: [PATCH 2/2] soundWire: intel_auxdevice: resume 'sdw-master' on startup and system resume

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Message-ID: <20230804094459.GS103419@ediswmail.ad.cirrus.com>
Date:   Fri, 4 Aug 2023 09:44:59 +0000
From:   Charles Keepax <ckeepax@...nsource.cirrus.com>
To:     Bard Liao <yung-chuan.liao@...ux.intel.com>
CC:     <alsa-devel@...a-project.org>, <vkoul@...nel.org>,
        <vinod.koul@...aro.org>, <linux-kernel@...r.kernel.org>,
        <pierre-louis.bossart@...ux.intel.com>, <bard.liao@...el.com>
Subject: Re: [PATCH 2/2] soundWire: intel_auxdevice: resume 'sdw-master' on
 startup and system resume

On Thu, Aug 03, 2023 at 02:52:20PM +0800, Bard Liao wrote:
> From: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
> 
> The SoundWire bus is handled with a dedicated device, which is placed
> between the Intel auxiliary device and peripheral devices, e.g.
> 
> soundwire_intel.link.0/sdw-master-0/sdw:0:025d:0711:01
> 
> The functionality of this 'sdw-master' device is limited, specifically
> for pm_runtime the ASoC framework will not rely on
> pm_runtime_get_sync() since it does not register any components. It
> will only change status thanks to the parent-child relationship which
> guarantees that the 'sdw-master' device will be pm_runtime resumed
> before any peripheral device.
> 
> However on startup and system resume it's possible that only the
> auxiliary device is pm_runtime active, and the peripheral will only
> become active during its io_init routine, leading to another
> occurrence of the error reported by the pm_runtime framework:
> 
> rt711 sdw:0:025d:0711:00: runtime PM trying to activate child device
> sdw:0:025d:0711:00 but parent (sdw-master-0) is not active
> 
> This patch suggests aligning the sdw-master device status to that of
> the auxiliary device. The difference between the two is completely
> notional and their pm_status shouldn't be different during the startup
> and system resume steps.
> 
> This problem was exposed by recent changes in the timing of the bus
> reset, but was present in this driver since we introduced pm_runtime
> support.
> 
> Closes: https://github.com/thesofproject/linux/issues/4328
> Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
> Reviewed-by: Ranjani Sridharan <ranjani.sridharan@...ux.intel.com>
> Reviewed-by: Rander Wang <rander.wang@...el.com>
> Signed-off-by: Bard Liao <yung-chuan.liao@...ux.intel.com>
> ---

Tested-by: Charles Keepax <ckeepax@...nsource.cirrus.com>

Thanks,
Charles