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

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Date:   Thu, 30 Sep 2021 08:29:10 -0500
From:   Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
To:     Ryan Lee <RyanS.Lee@...imintegrated.com>,
        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>,
        "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


> I do not see #3063 issue on my side. No initialization failure or time-out has occurred.

It's rather random, we've only seen the error in long daily tests.

> Now I'm trying to solve the issue with max98373_io_init() function as suggested instead of adding
> regmap_cache_dirty() in the suspend function.
> max98373_io_init() was not called from max98373_update_status() when audio resume because
> max98373->hw_init was 1 and Status was SDW_SLAVE_ATTACHED.
> max98373_update_status() do not get SDW_SLAVE_UNATTACHED.
> I confirmed that the issue could be resolved if SDW_SLAVE_UNATTACHED event arrives at
> max98373_update_status() before SDW_SLAVE_ATTACHED is triggered.
> Actually sdw_handle_slave_status() get SDW_SLAVE_UNATTACHED but this function exits at
> https://github.com/thesofproject/linux/blob/topic/sof-dev/drivers/soundwire/bus.c#L1765
> before reaching to https://github.com/thesofproject/linux/blob/topic/sof-dev/drivers/soundwire/bus.c#L1825
> I'm not sure how to solve this issue because this code is commonly
used for other Soundwire drivers as well.
>

There may be a confusion here.

The SoundWire spec says the device will show up as Device #0. That means
the status[0] = ATTACHED.

The driver reads the devID registers and programs the device number N.
The device will then report as device #N in PING frames. The controller
hardware will detect that device and call the function to update the
status a second time.

> I share the debug messages for the resume event as your reference.
> [  127.490644] [DEBUG3] intel_resume_runtime
> [  127.490655] [DEBUG3] intel_resume_runtime SDW_INTEL_CLK_STOP_BUS_RESET
> [  127.490658] [DEBUG3] intel_init
> [  127.490660] [DEBUG3] intel_link_power_up
> [  127.490977] [DEBUG3] intel_resume_runtime SDW_UNATTACH_REQUEST_MASTER_RESET ..
> [  127.490980] [DEBUG4] sdw_clear_slave_status request: 1
> [  127.490983] [DEBUG4] sdw_modify_slave_status, ID:7, status: 0
> [  127.490986] [DEBUG4] sdw_modify_slave_status, ID:3, status: 0
> [  127.490994] [DEBUG3] intel_shim_wake wake_enable:0
> [  127.491060] [DEBUG3] intel_shim_wake wake_enable:0
> [  127.491191] [DEBUG] max98373_resume, first_hw_init: 1, unattach_request: 1
> [  127.491194] [DEBUG] max98373_resume, INF MODE: 0
> [  127.491953] [DEBUG4] sdw_handle_slave_status IN
> [  127.491956] [DEBUG4] sdw_handle_slave_status, status[1] : 0, slave->status: 0, id:7	// UNATTACHED
> [  127.491958] [DEBUG4] sdw_handle_slave_status, status[2] : 0, slave->status: 0, id:3
> [  127.491960] [DEBUG4] sdw_handle_slave_status IN2 status[0] = 1
> [  127.492808] [DEBUG4] sdw_handle_slave_status IN
> [  127.492810] [DEBUG4] sdw_handle_slave_status, status[1] : 1, slave->status: 0, id:7	// ATTACHED
> [  127.492812] [DEBUG4] sdw_handle_slave_status, status[2] : 1, slave->status: 0, id:3
> [  127.492814] [DEBUG4] sdw_handle_slave_status IN2 status[0] = 0
> [  127.492816] [DEBUG4] sdw_handle_slave_status IN3
> [  127.492818] [DEBUG4] sdw_handle_slave_status status[1] = SDW_SLAVE_ATTACHED, slave->status : 0, slave:7, prev_status:0
> [  127.492820] [DEBUG4] sdw_modify_slave_status, ID:7, status: 1
> [  127.493008] [DEBUG4] sdw_update_slave_status update_status(1) IN slave:7
> [  127.493010] [DEBUG4] sdw_update_slave_status update_status(1) OUT
> [  127.493012] [DEBUG] max98373_update_status IN hw_init:1, status: 1, slave :7
> [  127.493015] [DEBUG] max98373_update_status IN2 hw_init:1, max98373->first_hw_init: 1, status: 1
> [  127.493017] [DEBUG4] sdw_handle_slave_status status[2] = SDW_SLAVE_ATTACHED, slave->status : 0, slave:3, prev_status:0
> [  127.493019] [DEBUG4] sdw_modify_slave_status, ID:3, status: 1
> [  127.493199] [DEBUG4] sdw_update_slave_status update_status(1) IN slave:3
> [  127.493201] [DEBUG4] sdw_update_slave_status update_status(1) OUT
> [  127.493204] [DEBUG] max98373_update_status IN hw_init:1, status: 1, slave :3
> [  127.493207] [DEBUG] max98373_update_status IN2 hw_init:1, max98373->first_hw_init: 1, status: 1

I don't really see anything in this sequence that differs from my
explanations?

The update_status() is only called when the device has a non-zero device
number.

There may be a real problem with update_status() not being called but I
just don't see it so far.

One way to improve the traces would be to use dev_dbg, that way we'd
have a trace of which device is being handled. There are two devices
managed by the same driver, a trace with pr_dbg doesn't tell us much.