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Date:   Wed, 17 Feb 2021 12:26:18 -0800
From:   Dmitry Torokhov <dmitry.torokhov@gmail.com>
To:     Ronald =?iso-8859-1?Q?Tschal=E4r?= <ronald@innovation.ch>
Cc:     "Gustavo A. R. Silva" <gustavoars@kernel.org>,
        Sergiu Cuciurean <sergiu.cuciurean@analog.com>,
        Lee Jones <lee.jones@linaro.org>, linux-input@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] Input: applespi: Add trace_event module param for
 early tracing.
Message-ID: <YC176rlGQeyKuOpn@google.com>
References: <20210217190718.11035-1-ronald@innovation.ch>
 <20210217190718.11035-3-ronald@innovation.ch>
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Hi Ronald,

On Wed, Feb 17, 2021 at 11:07:18AM -0800, Ronald Tschal?r wrote:
> The problem is that tracing can't be set via sysfs until the module is
> loaded, at which point the keyboard and trackpad initialization commands
> have already been run and hence tracing can't be used to debug problems
> here.
> 
> Adding this param allows tracing to be enabled for messages sent and
> received during module probing. It takes comma-separated list of events,
> e.g.
> 
>   trace_event=applespi_tp_ini_cmd,applespi_bad_crc

You can unbind and rebind a device to a driver via sysfs as many times
as needed (see bind and unbind driver sysfs attributes), so I believe

Thanks.

-- 
Dmitry