linux-kernel - Re: [PATCH 3/3] sound: don't call skl_init

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Date:   Tue, 11 Sep 2018 08:17:05 +0200
From:   Takashi Iwai <tiwai@...e.de>
To:     "Yu Zhao" <yuzhao@...gle.com>
Cc:     "Mark Brown" <broonie@...nel.org>, <alsa-devel@...a-project.org>,
        "Guneshwor Singh" <guneshwor.o.singh@...el.com>,
        "Naveen Manohar" <naveen.m@...el.com>,
        "Pankaj Bharadiya" <pankaj.laxminarayan.bharadiya@...el.com>,
        "Rakesh Ughreja" <rakesh.a.ughreja@...el.com>,
        "Sanyog Kale" <sanyog.r.kale@...el.com>,
        "Sriram Periyasamy" <sriramx.periyasamy@...el.com>,
        "Vinod Koul" <vkoul@...nel.org>,
        "Liam Girdwood" <liam.r.girdwood@...ux.intel.com>,
        "Pierre-Louis Bossart" <pierre-louis.bossart@...ux.intel.com>,
        "Jie Yang" <yang.jie@...ux.intel.com>,
        "Jaroslav Kysela" <perex@...ex.cz>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] sound: don't call skl_init_chip() to reset intel skl soc

On Mon, 10 Sep 2018 23:23:58 +0200,
Yu Zhao wrote:
> 
> Internally, skl_init_chip() calls snd_hdac_bus_init_chip() which
> 1) sets bus->chip_init to prevent multiple entrances before device
> is stopped; 2) enables interrupt.
> 
> We shouldn't use it for the purpose of resetting device only because
> 1) when we really want to initialize device, we won't be able to do
> so; 2) we are ready to handle interrupt yet, and kernel crashes when
> interrupt comes in.
> 
> Rename azx_reset() to snd_hdac_bus_reset_link(), and use it to reset
> device properly.
> 
> Fixes: 60767abcea3d ("ASoC: Intel: Skylake: Reset the controller in probe")
> Signed-off-by: Yu Zhao <yuzhao@...gle.com>

That makes sense.

And I noticed that the legacy HD-audio driver potentially needs the
same reset (although we haven't heard of any problem for years).

So now I wonder whether this requirement of reset is really mandatory
for the real hardware, or just theoretical...

In anyway,

Reviewed-by: Takashi Iwai <tiwai@...e.de>


thanks,

Takashi