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Subject: Re: [PATCH 3/4] scsi: ufs-debugfs: Add user-defined
 exception_event_mask
To:     Bean Huo <huobean@gmail.com>,
        "Martin K . Petersen" <martin.petersen@oracle.com>,
        "James E . J . Bottomley" <jejb@linux.ibm.com>
Cc:     linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org,
        Alim Akhtar <alim.akhtar@samsung.com>,
        Avri Altman <avri.altman@wdc.com>,
        Can Guo <cang@codeaurora.org>,
        Stanley Chu <stanley.chu@mediatek.com>
References: <20210119141542.3808-1-adrian.hunter@intel.com>
 <20210119141542.3808-4-adrian.hunter@intel.com>
 <85b6cbb805e97081a676aeb30fe76f059eba192e.camel@gmail.com>
From:   Adrian Hunter <adrian.hunter@intel.com>
Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki,
 Business Identity Code: 0357606 - 4, Domiciled in Helsinki
Message-ID: <b7a812ed-8965-76cf-3d05-be2486fcaed2@intel.com>
Date:   Wed, 3 Feb 2021 11:56:05 +0200
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On 3/02/21 11:45 am, Bean Huo wrote:
> On Tue, 2021-01-19 at 16:15 +0200, Adrian Hunter wrote:
>> Allow users to enable specific exception events via debugfs.
>>
>> The bits enabled by the driver ee_drv_ctrl are separated from the
>> bits
>> enabled by the user ee_usr_ctrl. The control mask ee_mask_ctrl is the
>> logical-or of those two. A mutex is needed to ensure that the masks
>> match
>> what was written to the device.
> 
> Hallo Adrian

Hi Bean

Thanks for the review

> 
> Would you like sharing the advantage of this debugfs node comparing to
> sysfs node "attributes/exception_event_control(if it is writable)"?

Primarily this is being done as a debug interface, but the user's exception
events also need to be kept separate from the driver's ones.

> what is the value of this?

To be able to determine if the UFS device is being affected by exception events.

> Also, now I can disable/enable UFS event over ufs-bsg.

That will be overwritten by the driver when it updates the e.g. bkops
control, or sometimes also suspend/resume.