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From: Richard Fitzgerald <rf@opensource.cirrus.com>
To: Mark Brown <broonie@kernel.org>,
	Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Cc: <rander.wang@linux.intel.com>, <shumingf@realtek.com>,
	<patches@opensource.cirrus.com>, <alsa-devel@alsa-project.org>,
	<linux-kernel@vger.kernel.org>,
	Lucas Tanure <tanureal@opensource.cirrus.com>
Subject: Re: [PATCH] ASoC: dapm: Revert "use component prefix when checking widget names"
Date: Fri, 23 Jul 2021 16:17:26 +0100	[thread overview]
Message-ID: <1952b7f0-3c0a-faa4-8a1b-1a8bc4fff473@opensource.cirrus.com> (raw)
In-Reply-To: <a882a9e0-db05-2f89-abb9-8b308ccb56c8@opensource.cirrus.com>

On 22/07/2021 10:55, Richard Fitzgerald wrote:
> On 05/07/2021 17:50, Mark Brown wrote:
>> On Sat, Jul 03, 2021 at 01:50:34PM +0100, Richard Fitzgerald wrote:
>>
>>> That commit breaks all users of the snd_soc_component_*_pin() functions
>>> because it results in the prefix being added twice. It also breaks code
>>> that correctly uses the snd_soc_dapm_*_pin() functions.
>>
>>> Use the snd_soc_component_*_pin() functions if you want the component
>>> prefix to be prepended automatically.
>>
>>> Use the raw snd_soc_dapm_*_pin() functions if the caller has the full
>>> name that should be matched exactly.
>>
>> I'm not sure the analysis of which function to use when is correct or
>> what we want here (though it will work ATM), though looking again more
>> closely at the patch it doesn't look entirely right either.  The way
>> this used to be done, and the way that older code will most likely
>> assume things work, was that the DAPM functions would first try to match
>> on the local DAPM context before falling back to doing a global match.
>> This is what the fallback loop is intended to do, and the dapm functions
>> are passing the "search other contexts" flag into dapm_find_widget().
>>
>> I'd not expect the distinction you seem to expect between component and
>> DAPM and we probably have a bunch of older drivers that aren't working
>> correctly like the Realtek driver mentioned in the original fix.  I
>> think what needs to happen is that dapm_find_widget() needs to be
>> checking both the prefixed and non-prefixed names, and that the
>> component stuff shouldn't need to bother and just be a convenience
>> wrapper for users that happene to have a component to hand.
>> Alternatively we need to do an audit of all the non-machine drivers to
>> switch them to use the component functions exclusively (and possibly
>> some of the machine drivers as well), most of the CODEC users look to be
>> a small number of Wolfson/Cirrus ones.
>>
> 
> I don't mind if someone wants to change the core dapm functions if that
> is generally useful, providing that it also updates all callers of those
> functions to still work.
> 
> Changing the behaviour of core code to fix the Realtek driver without
> updating other callers of those functions is a problem.

Just to point out this is breaking stuff right now. It's not just
theoretical.

  reply	other threads:[~2021-07-23 15:19 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-03 12:50 Richard Fitzgerald
2021-07-05 16:50 ` Mark Brown
2021-07-22  9:55   ` Richard Fitzgerald
2021-07-23 15:17     ` Richard Fitzgerald [this message]
2021-07-23 15:24       ` Mark Brown
2021-07-28 16:09     ` Mark Brown
2021-07-28 18:29       ` Richard Fitzgerald
2021-07-28 23:40         ` Mark Brown

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