linux-kernel - Re: [EXTERNAL] Re: [PATCH] ASoC: max98373: Mark cache dirty before entering sleep

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <0af258d4-e33c-15ec-5dcc-a1c9961c0740@linux.intel.com>
Date:   Mon, 27 Sep 2021 12:23:06 -0500
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
To:     Mark Brown <broonie@...nel.org>
Cc:     "guennadi.liakhovetski@...ux.intel.com" 
        <guennadi.liakhovetski@...ux.intel.com>,
        "alsa-devel@...a-project.org" <alsa-devel@...a-project.org>,
        "ryan.lee.maxim@...il.com" <ryan.lee.maxim@...il.com>,
        Ryan Lee <RyanS.Lee@...imintegrated.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "tiwai@...e.com" <tiwai@...e.com>,
        "lgirdwood@...il.com" <lgirdwood@...il.com>,
        "sathya.prakash.m.r@...el.com" <sathya.prakash.m.r@...el.com>,
        "yung-chuan.liao@...ux.intel.com" <yung-chuan.liao@...ux.intel.com>
Subject: Re: [EXTERNAL] Re: [PATCH] ASoC: max98373: Mark cache dirty before
 entering sleep



On 9/27/21 12:10 PM, Mark Brown wrote:
> On Mon, Sep 27, 2021 at 11:48:56AM -0500, Pierre-Louis Bossart wrote:
>> On 9/27/21 11:06 AM, Mark Brown wrote:
> 
>>> More specifically what it does is make the invalidation of the register
>>> cache unconditional.  It doesn't really matter if the invalidation is
>>> done on suspend or resume, so long as it happens before we attempt to
>>> resync - this could also be done by deleting the first_hw_init check.
> 
>> Mark, that's exactly my point: if the amp rejoins the bus, we will
>> *always* mark the cache as dirty, before the resync is done in the
>> resume sequence.
> 
> Ah, yes - I see.
> 
>> I am really trying to figure out if we have a major flaw in the resume
>> sequence and why things are different in the case of the Maxim amp.
> 
>> Instead of changing the suspend sequence, can we please try to modify
>> the max98373_io_init() routine to unconditionally flag the cache as
>> dirty, maybe this points to a problem with the management of the
>> max98373->first_hw_init flag.
> 
> A quick survey of other drivers suggests that this pattern should be
> factored out into some helpers as it looks like there's several ways of
> implementing it that look very similar but not quite the same...

No disagreement here, we tried really hard to enforce a common pattern
for suspend-resume, but i just noticed that the maxim amp driver is
different on suspend (resume is consistent with the rest).


static int __maybe_unused rt711_dev_suspend(struct device *dev)
{
	struct rt711_priv *rt711 = dev_get_drvdata(dev);

	if (!rt711->hw_init)
		return 0;

	cancel_delayed_work_sync(&rt711->jack_detect_work);
	cancel_delayed_work_sync(&rt711->jack_btn_check_work);
	cancel_work_sync(&rt711->calibration_work);

	regcache_cache_only(rt711->regmap, true);

	return 0;
}

static int __maybe_unused rt1308_dev_suspend(struct device *dev)
{
	struct rt1308_sdw_priv *rt1308 = dev_get_drvdata(dev);

	if (!rt1308->hw_init)
		return 0;

	regcache_cache_only(rt1308->regmap, true);

	return 0;
}

static __maybe_unused int max98373_suspend(struct device *dev)
{
	struct max98373_priv *max98373 = dev_get_drvdata(dev);
	int i;

<<<< missing test

	/* cache feedback register values before suspend */
	for (i = 0; i < max98373->cache_num; i++)
		regmap_read(max98373->regmap, max98373->cache[i].reg,
&max98373->cache[i].val);

<<<< why is this needed???

	regcache_cache_only(max98373->regmap, true);

	return 0;
}