From: Adrian Hunter <adrian.hunter@intel.com>
To: Bean Huo <huobean@gmail.com>,
alim.akhtar@samsung.com, avri.altman@wdc.com,
asutoshd@codeaurora.org, jejb@linux.ibm.com,
martin.petersen@oracle.com, stanley.chu@mediatek.com,
beanhuo@micron.com, bvanassche@acm.org, tomas.winkler@intel.com,
cang@codeaurora.org
Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v6 1/6] scsi: ufs: Add "wb_on" sysfs node to control WB on/off
Date: Tue, 19 Jan 2021 12:00:11 +0200 [thread overview]
Message-ID: <9ad2cf1a-68df-47ef-9fe7-01954d2d6181@intel.com> (raw)
In-Reply-To: <fabf0e83387f6155efea521a15b00bb1225d35a4.camel@gmail.com>
On 19/01/21 11:33 am, Bean Huo wrote:
> On Tue, 2021-01-19 at 09:01 +0200, Adrian Hunter wrote:
>> On 18/01/21 10:10 pm, Bean Huo wrote:
>>> From: Bean Huo <beanhuo@micron.com>
>>>
>>> Currently UFS WriteBooster driver uses clock scaling up/down to set
>>> WB on/off, for the platform which doesn't support
>>> UFSHCD_CAP_CLK_SCALING,
>>> WB will be always on. Provide a sysfs attribute to enable/disable
>>> WB
>>> during runtime. Write 1/0 to "wb_on" sysfs node to enable/disable
>>> UFS WB.
>>
>> Is it so, that after a full reset, WB is always enabled again? Is
>> that
>> intended?
>
> Hello Adrian
> Good questions. yes, after a full reset, the UFS device side by default
> is wb disabled, then WB will be always enabled agaion in
> ufshcd_wb_config(hba). but, for the platform which
> supports UFSHCD_CAP_CLK_SCALING, wb will be disabled again while clk
> scaling down and enabled while clk scaling up.
>
> Regarding the last question, I think OEM wants to do that. maybe they
> suppose there will be a lot of writing after reset?? From the UFS
> device's point of view, the control of WB is up to the user.
If it is by design enabled after reset, then perhaps it should be mentioned
in the sysfs documentation.
next prev parent reply other threads:[~2021-01-19 14:38 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-18 20:10 [PATCH v6 0/6] Several changes for UFS WriteBooster Bean Huo
2021-01-18 20:10 ` [PATCH v6 1/6] scsi: ufs: Add "wb_on" sysfs node to control WB on/off Bean Huo
2021-01-19 7:01 ` Adrian Hunter
2021-01-19 9:33 ` Bean Huo
2021-01-19 10:00 ` Adrian Hunter [this message]
2021-01-19 16:31 ` Bean Huo
2021-01-18 20:10 ` [PATCH v6 2/6] docs: ABI: Add wb_on documentation for UFS sysfs Bean Huo
2021-01-18 20:10 ` [PATCH v6 3/6] scsi: ufs: Changes comment in the function ufshcd_wb_probe() Bean Huo
2021-01-18 20:10 ` [PATCH v6 4/6] scsi: ufs: Remove two WB related fields from struct ufs_dev_info Bean Huo
2021-01-18 20:10 ` [PATCH v6 5/6] scsi: ufs: Group UFS WB related flags to " Bean Huo
2021-01-18 20:10 ` [PATCH v6 6/6] scsi: ufs: Cleanup WB buffer flush toggle implementation Bean Huo
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