From: Nicolin Chen <nicoleotsuka@gmail.com>
To: "S.j. Wang" <shengjiu.wang@nxp.com>
Cc: "alsa-devel@alsa-project.org" <alsa-devel@alsa-project.org>,
"timur@kernel.org" <timur@kernel.org>,
"Xiubo.Lee@gmail.com" <Xiubo.Lee@gmail.com>,
"festevam@gmail.com" <festevam@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"broonie@kernel.org" <broonie@kernel.org>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH] ASoC: fsl_esai: fix the channel swap issue after xrun
Date: Wed, 5 Jun 2019 17:16:45 -0700 [thread overview]
Message-ID: <20190606001644.GA20103@Asurada-Nvidia.nvidia.com> (raw)
In-Reply-To: <VE1PR04MB6479D7512EDE1217228033CAE3160@VE1PR04MB6479.eurprd04.prod.outlook.com>
Hello Shengjiu,
On Wed, Jun 05, 2019 at 10:29:37AM +0000, S.j. Wang wrote:
> > > ETDR is not volatile, if we mark it is volatile, is it correct?
> >
> > Well, you have a point -- it might not be ideally true, but it sounds like a
> > correct fix to me according to this comments.
> >
> > We can wait for Mark's comments or just send a patch to the mail list for
> > review.
>
> I test this patch, we don't need to reset the FIFO, and regcache_sync didn't
> Write the ETDR even the EDTR is not volatile. This fault maybe caused by
The fsl_esai driver uses FLAT type cache so regcache_sync() would
go through regcache_default_sync() that would bypass cache sync at
the regcache_reg_needs_sync() check when the cached register value
matches its default value: in case of ETDR who has a default value
0x0, it'd just "continue" without doing that _regmap_write() when
the cached value equals to 0x0.
> Legacy, in the beginning we add this patch in internal branch, there maybe
> Something cause this issue, but now can't reproduced.
The "legacy" case might happen to have two mismatched ETDR values
between the cached value and default 0x0. And I am worried it may
appear once again someday.
So I feel we still need to change ETDR to volatile type. And for
your question "ETDR is not volatile, if we mark it is volatile,
is it correct?", I double checked the definition of volatile_reg,
and it says:
* @volatile_reg: Optional callback returning true if the register
* value can't be cached. If this field is NULL but
So it seems correct to me then, as the "volatile" should be also
transcribed as "non-cacheable".
Thanks
Nicolin
next prev parent reply other threads:[~2019-06-06 0:18 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-05 10:29 [PATCH] ASoC: fsl_esai: fix the channel swap issue after xrun S.j. Wang
2019-06-06 0:16 ` Nicolin Chen [this message]
-- strict thread matches above, loose matches on Subject: below --
2019-05-23 11:04 S.j. Wang
2019-05-23 22:50 ` Nicolin Chen
2019-05-23 9:53 S.j. Wang
2019-05-23 10:10 ` Nicolin Chen
2019-05-17 3:09 S.j. Wang
2019-05-17 20:01 ` Nicolin Chen
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