linux-kernel - Re: [PATCH] ASoC: fsl_ssi: remove explicit register defaults

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Message-ID: <CAOMZO5DwQza+jDdkA80v4wkrB56y53tOjkP2-36YNq2WBLodaA@mail.gmail.com>
Date:	Mon, 1 Feb 2016 10:05:46 -0200
From:	Fabio Estevam <festevam@...il.com>
To:	"Maciej S. Szmigiero" <mail@...iej.szmigiero.name>
Cc:	"alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
	Timur Tabi <timur@...i.org>,
	Nicolin Chen <nicoleotsuka@...il.com>,
	Xiubo Li <Xiubo.Lee@...il.com>,
	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>,
	"linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] ASoC: fsl_ssi: remove explicit register defaults

Hi Maciej,

On Mon, Jan 18, 2016 at 5:07 PM, Maciej S. Szmigiero
<mail@...iej.szmigiero.name> wrote:
> There is no guarantee that on fsl_ssi module load
> SSI registers will have their power-on-reset values.
>
> In fact, if the driver is reloaded the values in
> registers will be whatever they were set to previously.
>
> However, the cache needs to be fully populated at probe
> time to avoid non-atomic allocations during register
> access.
>
> Special case here is imx21-class SSI, since
> according to datasheet it don't have SACC{ST,EN,DIS}
> regs.
>
> This fixes hard lockup on fsl_ssi module reload,
> at least in AC'97 mode.
>
> Fixes: 05cf237972fe ("ASoC: fsl_ssi: Add driver suspend and resume to support MEGA Fast")
>
> Signed-off-by: Maciej S. Szmigiero <mail@...iej.szmigiero.name>

I know I have already tested this and it worked fine on a mx6sabresd,
but running linux-next 20160201 on a mx6sl-evk the ssi driver does not
probe anymore:

[    2.216954] fsl-asoc-card sound: ASoC: CPU DAI (null) not registered
[    2.223412] fsl-asoc-card sound: snd_soc_register_card failed (-517)
[    2.230258] imx-wm8962 sound: ASoC: CPU DAI 202c000.ssi not registered
[    2.236806] imx-wm8962 sound: snd_soc_register_card failed (-517)
[    2.244782] snvs_rtc 20cc000.snvs:snvs-rtc-lp: setting system clock
to 1970-01-01 00:01:14 UTC (74)
[    2.285864] fsl-asoc-card sound: ASoC: CPU DAI (null) not registered
[    2.292335] fsl-asoc-card sound: snd_soc_register_card failed (-517)
[    2.299572] imx-wm8962 sound: ASoC: CPU DAI 202c000.ssi not registered
[    2.306121] imx-wm8962 sound: snd_soc_register_card failed (-517)

Reverting this patch fixes the problem.

Wandboard also has the same issue:

http://arm-soc.lixom.net/bootlogs/next/next-20160201/wandboard-arm-imx_v6_v7_defconfig.html

Any suggestions?

Thanks