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Message-ID: <8f57c62f-c427-f5df-d517-d4025fe7c65d@linux.intel.com>
Date:   Mon, 15 May 2023 10:28:00 -0500
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Subject: Re: [PATCH 1/2] ASoC: SOF: mediatek: add mt8188 audio support
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To:     Mark Brown <broonie@kernel.org>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@collabora.com>
Cc:     Trevor Wu <trevor.wu@mediatek.com>, peter.ujfalusi@linux.intel.com,
        yung-chuan.liao@linux.intel.com, ranjani.sridharan@linux.intel.com,
        kai.vehmanen@linux.intel.com, daniel.baluta@nxp.com,
        lgirdwood@gmail.com, tiwai@suse.com, perex@perex.cz,
        matthias.bgg@gmail.com, yc.hung@mediatek.com,
        tinghan.shen@mediatek.com, sound-open-firmware@alsa-project.org,
        alsa-devel@alsa-project.org, linux-mediatek@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
References: <20230515052540.9037-1-trevor.wu@mediatek.com>
 <20230515052540.9037-2-trevor.wu@mediatek.com>
 <7c784932-951a-65c0-c48f-bfa4c098b2e1@collabora.com>
 <ZGJKPuf1FX4AYLXl@finisterre.sirena.org.uk>
From:   Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
In-Reply-To: <ZGJKPuf1FX4AYLXl@finisterre.sirena.org.uk>
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On 5/15/23 10:05, Mark Brown wrote:
> On Mon, May 15, 2023 at 01:25:44PM +0200, AngeloGioacchino Del Regno wrote:
>> Il 15/05/23 07:25, Trevor Wu ha scritto:
> 
>>> +{
>>> +	/* common defaults */
>>> +	memcpy(&sof_mt8188_ops, &sof_mt8186_ops, sizeof(struct snd_sof_dsp_ops));
> 
>> Never use sizeof(type), always use destination var size! Anyway, there's more.
>>
>> I don't think we need to perform this memcpy: we'll never see an instance of
>> both mt8186 and mt8188 drivers on the same machine, so you can safely just use
>> sof_mt8186_ops for mt8188...
> 
>>> +	sof_mt8188_ops.drv = mt8188_dai;
> 
>> ...which obviously means that this becomes
> 
>> 	sof_mt8186_ops.drv = mt8188_dai;
> 
> This does have the issue that it then means the ops struct isn't const
> which isn't ideal.  It's also not the end of the world though so I don't
> have super strong feelings.

We do the same for Intel devices, we have a common structure which is
copied and only the members that differ in specific SOCs are updated.
You're right that it's not constant, but it avoids copy-paste of a
rather large structure just to change a couple of lines.