linux-kernel - Re: [PATCH] regmap: maple: Don't sync read-only registers

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Date:   Tue, 13 Jun 2023 12:34:45 +0200
From:   Takashi Iwai <tiwai@...e.de>
To:     Mark Brown <broonie@...nel.org>
Cc:     linux-kernel@...r.kernel.org, alsa-devel@...a-project.org
Subject: Re: [PATCH] regmap: maple: Don't sync read-only registers

On Tue, 13 Jun 2023 12:16:37 +0200,
Mark Brown wrote:
> 
> On Tue, Jun 13, 2023 at 09:45:11AM +0200, Takashi Iwai wrote:
> > regcache_maple_sync() tries to sync all cached values no matter
> > whether it's writable or not.  OTOH, regache_sync_val() does care the
> > wrtability and returns -EIO for a read-only register.  This results in
> > an error message like:
> >   snd_hda_codec_realtek hdaudioC0D0: Unable to sync register 0x2f0009. -5
> > and the sync loop is aborted incompletely.
> > 
> > This patch adds the writable register check in the loop for addressing
> > the bug.
> 
> This should be in _needs_sync().

I thought it's a different logic?  regacahe_reg_needs_sync() checks
only whether it's a default value, and other call paths already check
regmap_writeable().

But I can put the check there instead if you still prefer, too.


thanks,

Takashi