From: Nicolin Chen <nicoleotsuka@gmail.com>
To: "broonie@kernel.org" <broonie@kernel.org>,
"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>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH] ASoC: fsl_esai: fix the channel swap issue after xrun
Date: Thu, 23 May 2019 03:10:56 -0700 [thread overview]
Message-ID: <20190523101055.GA28470@Asurada-Nvidia.nvidia.com> (raw)
In-Reply-To: <VE1PR04MB647934199C3AA60759BED888E3010@VE1PR04MB6479.eurprd04.prod.outlook.com>
Hello Shengjiu,
On Thu, May 23, 2019 at 09:53:42AM +0000, S.j. Wang wrote:
> > > + /*
> > > + * Add fifo reset here, because the regcache_sync will
> > > + * write one more data to ETDR.
> > > + * Which will cause channel shift.
> >
> > Sounds like a bug to me...should fix it first by marking the data registers as
> > volatile.
> >
> The ETDR is a writable register, it is not volatile. Even we change it to
> Volatile, I don't think we can't avoid this issue. for the regcache_sync
> Just to write this register, it is correct behavior.
Is that so? Quoting the comments of regcache_sync():
"* regcache_sync - Sync the register cache with the hardware.
*
* @map: map to configure.
*
* Any registers that should not be synced should be marked as
* volatile."
If regcache_sync() does sync volatile registers too as you said,
I don't mind having this FIFO reset WAR for now, though I think
this mismatch between the comments and the actual behavior then
should get people's attention.
Thank you
next prev parent reply other threads:[~2019-05-23 10:13 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-23 9:53 [PATCH] ASoC: fsl_esai: fix the channel swap issue after xrun S.j. Wang
2019-05-23 10:10 ` Nicolin Chen [this message]
-- strict thread matches above, loose matches on Subject: below --
2019-06-05 10:29 S.j. Wang
2019-06-06 0:16 ` Nicolin Chen
2019-05-23 11:04 S.j. Wang
2019-05-23 22:50 ` Nicolin Chen
2019-05-17 3:09 S.j. Wang
2019-05-17 20:01 ` Nicolin Chen
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