Date: Fri, 15 Dec 2017 19:17:39 -0800
From: Brian Norris <briannorris@chromium.org>
To: Oder Chiou <oder_chiou@realtek.com>, Bard Liao <bardliao@realtek.com>,
        Liam Girdwood <lgirdwood@gmail.com>, Mark Brown <broonie@kernel.org>
Cc: Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>,
        alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org,
        Matthias Kaehlcke <mka@chromium.org>,
        Jeffy Chen <jeffy.chen@rock-chips.com>,
        linux-rockchip@lists.infradead.org,
        Jimmy Cheng-Yi Chiang <cychiang@google.com>
Subject: Re: [PATCH for-4.15] ASoC: rt5514: don't assume rt5514 component was
 "attached"
Message-ID: <20171216031738.GA220575@google.com>
References: <20171216011230.107527-1-briannorris@chromium.org>
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+ others

On Fri, Dec 15, 2017 at 05:12:30PM -0800, Brian Norris wrote:
> I've found that on Google's "Kevin" Chromebook, the rt5514 codec might
> not be set up completely, yet its device is still present, and therefore
> its PM suspend/resume is called. This hits a NULL pointer exception,
> since we never had the chance to set our drvdata pointer.
> 
> This resolves crashes seen when trying to resume my system.
> 
> Fixes: e9c50aa6bd39 ("ASoC: rt5514-spi: check irq status to schedule data copy in resume function")
> Signed-off-by: Brian Norris <briannorris@chromium.org>
> ---
> This is a v4.15-rc1 regression

I see that this is probably a bug on its own, which should be fixed on
its own (e.g., with the $subject patch), but FYI I was also pointed at
this patch, which also "resolves" this problem by fixing the rt5514 DAI
setup:

https://patchwork.kernel.org/patch/10067725/
[PATCH] ASoC: rockchip: Use dummy_dai for rt5514 dsp dailink

Would be nice to see it get handled too, possibly in 4.15 as well (I
think that's a regression too?).

Brian

> 
>  sound/soc/codecs/rt5514-spi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/sound/soc/codecs/rt5514-spi.c b/sound/soc/codecs/rt5514-spi.c
> index 2df91db765ac..9255afcf2c3a 100644
> --- a/sound/soc/codecs/rt5514-spi.c
> +++ b/sound/soc/codecs/rt5514-spi.c
> @@ -482,7 +482,7 @@ static int __maybe_unused rt5514_resume(struct device *dev)
>  	if (device_may_wakeup(dev))
>  		disable_irq_wake(irq);
>  
> -	if (rt5514_dsp->substream) {
> +	if (rt5514_dsp && rt5514_dsp->substream) {
>  		rt5514_spi_burst_read(RT5514_IRQ_CTRL, (u8 *)&buf, sizeof(buf));
>  		if (buf[0] & RT5514_IRQ_STATUS_BIT)
>  			rt5514_schedule_copy(rt5514_dsp);
> -- 
> 2.15.1.504.g5279b80103-goog
>