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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>
 <b7a812ed-8965-76cf-3d05-be2486fcaed2@intel.com>
 <372c6dbbda18cccdcf2b053ee87f2ada9640e2b8.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: <a4102d62-9101-c69d-c030-ec6a6bad7fc7@intel.com>
Date:   Thu, 4 Feb 2021 17:25:05 +0200
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On 4/02/21 4:58 pm, Bean Huo wrote:
> On Wed, 2021-02-03 at 11:56 +0200, Adrian Hunter wrote:
>>>
>>> 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.
> 
> Hi Adrian
> yes, I saw that, they are not tracked by driver.
> 
> I have one question that why "exception_event_mask" cannot represent
> the current QUERY_ATTR_IDN_EE_CONTROL value? only after writing it.

It represents only the user's exception events (ee_usr_mask), not the
driver's ones (ee_drv_mask) as well.  ee_usr_mask is updated after
successfully ensuring it is set on the device.