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Message-ID: <d3a2eb33-ea3e-43ac-a872-a7182404eee6@linux.intel.com>
Date:   Tue, 28 Nov 2023 11:49:44 -0600
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Subject: Re: [PATCH 2/2] ASoC: qcom: Move Soundwire runtime stream alloc to
 soundcards
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To:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc:     linux-arm-msm@vger.kernel.org, Andy Gross <agross@kernel.org>,
        Bjorn Andersson <andersson@kernel.org>,
        Konrad Dybcio <konrad.dybcio@linaro.org>,
        Vinod Koul <vkoul@kernel.org>,
        Bard Liao <yung-chuan.liao@linux.intel.com>,
        Sanyog Kale <sanyog.r.kale@intel.com>,
        Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        Banajit Goswami <bgoswami@quicinc.com>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Jaroslav Kysela <perex@perex.cz>,
        Takashi Iwai <tiwai@suse.com>, alsa-devel@alsa-project.org,
        linux-kernel@vger.kernel.org, linux-sound@vger.kernel.org
References: <20231128165638.757665-1-krzysztof.kozlowski@linaro.org>
 <20231128165638.757665-2-krzysztof.kozlowski@linaro.org>
 <4317ec5d-8eb8-4a2f-aebc-cc04f2aba145@linaro.org>
From:   Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
In-Reply-To: <4317ec5d-8eb8-4a2f-aebc-cc04f2aba145@linaro.org>
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On 11/28/23 10:59, Krzysztof Kozlowski wrote:
> On 28/11/2023 17:56, Krzysztof Kozlowski wrote:
>> Currently the Qualcomm Soundwire controller in its DAI startup op
>> allocates the Soundwire stream runtime.  This works fine for existing
>> designs, but has limitations for stream runtimes with multiple
>> controllers, like upcoming Qualcomm X1E80100 SoC with four WSA8840
>> speakers on two Soundwire controllers.
>>
>> When two Soundwire controllers are added to sound card codecs, Soundwire
>> startup() is called twice, one for each Soundwire controller, and second
>> execution overwrites what was set before.  During shutdown() this causes
>> double free.
>>
>> It is expected to have only one Soundwire stream runtime, thus it should
>> be allocated from SoC soundcard context startup(), not from each
>> Soundwire startup().  Such way will properly handle both cases: one and
>> two Soundwire controllers in the stream runtime.
>>
>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
>>
>> ---
>>
>> This is an entirely different approach than my previous try here:
>> https://lore.kernel.org/all/20231025144601.268645-1-krzysztof.kozlowski@linaro.org/
> 
> ... and I forgot to thank you Pierre-Louis for patient explanation of
> the case in my previous try. Your review was much appreciated!

You're welcome. It's good if we have multiple platforms using the
'stream' concept in similar ways.