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Message-ID: <b080405b-d1af-8a32-a429-b09250489f0c@linux.intel.com>
Date:   Thu, 30 Jun 2022 14:50:10 -0500
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Subject: Re: [PATCH v5 2/2] ASoC: cs35l41: Read System Name from ACPI _SUB to
 identify firmware
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To:     Mark Brown <broonie@kernel.org>
Cc:     Stefan Binding <sbinding@opensource.cirrus.com>,
        alsa-devel@alsa-project.org,
        "Rafael J . Wysocki" <rafael@kernel.org>,
        patches@opensource.cirrus.com, Liam Girdwood <lgirdwood@gmail.com>,
        linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org,
        Len Brown <lenb@kernel.org>
References: <20220630150135.1799535-1-sbinding@opensource.cirrus.com>
 <20220630150135.1799535-3-sbinding@opensource.cirrus.com>
 <2cc37f6d-72a7-9064-cad2-c6c6d21ede61@linux.intel.com>
 <Yr36wcXf1/bNS0a3@sirena.org.uk>
From:   Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
In-Reply-To: <Yr36wcXf1/bNS0a3@sirena.org.uk>
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On 6/30/22 14:34, Mark Brown wrote:
> On Thu, Jun 30, 2022 at 01:35:05PM -0500, Pierre-Louis Bossart wrote:
> 
>> It's my understanding that the _SUB method is optional, not required. It
>> may be wise to plan for a fallback, e.g to use DMI quirks or other
>> identifiers, no?
> 
> Presumably the fallback would go into cs35l41_acpi_get_name()?

That's what I had in mind, if this _SUB does not exist then you could
use something else instead of returning -ENODATA;

+	sub = acpi_get_subsystem_id(handle);
+	if (IS_ERR(sub))
+		return PTR_ERR(sub);
+
+	cs35l41->dsp.system_name = sub;