From: Can Guo <cang@codeaurora.org>
To: Stanley Chu <stanley.chu@mediatek.com>
Cc: kuohong.wang@mediatek.com, asutoshd@codeaurora.org,
nguyenb@codeaurora.org, hongwus@codeaurora.org,
rnayak@codeaurora.org, linux-scsi@vger.kernel.org,
kernel-team@android.com, saravanak@google.com,
salyzyn@google.com, Alim Akhtar <alim.akhtar@samsung.com>,
Avri Altman <avri.altman@wdc.com>,
"James E.J. Bottomley" <jejb@linux.ibm.com>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Bean Huo <beanhuo@micron.com>,
Colin Ian King <colin.king@canonical.com>,
Tomas Winkler <tomas.winkler@intel.com>,
Bart Van Assche <bvanassche@acm.org>,
Venkat Gopalakrishnan <venkatg@codeaurora.org>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v5 6/8] scsi: ufs: Add dev ref clock gating wait time support
Date: Thu, 06 Feb 2020 10:39:57 +0800 [thread overview]
Message-ID: <8b6603db0bb793365542c39d33a64a0e@codeaurora.org> (raw)
In-Reply-To: <1580950556.27391.11.camel@mtksdccf07>
On 2020-02-06 08:55, Stanley Chu wrote:
> Hi Can,
>
> On Wed, 2020-02-05 at 12:52 +0800, Can Guo wrote:
>
>
>> Hi Stanley,
>>
>> We used to ask vendors about it, 50 is somehow agreed by them. Do you
>> have a
>> better value in mind?
>>
>> For me, I just wanted to give it 10, so that we can directly use
>> usleep_range
>> with it, no need to decide whether to use udelay or usleep_range.
>
> Actually I do not have any value in mind because I guess the 50us here
> is just a margin time added for safety as your comments: "Give it more
> time to be on the safe side".
>
> An example case is that some vendors only specify 1us in
> bRefClkGatingWaitTime, so this 50us may be too long compared to
> device's
> requirement. If such device really needs this additional 50us, it shall
> be specified in bRefClkGatingWaitTime.
>
> So if this additional delay does not have any special reason or not
> mentioned by UFS specification, would you consider move it to vendor
> specific implementations. By this way, it would be more flexible to be
> controlled by vendors or by platforms.
>
> Thanks,
> Stanley
>
>>
>> Thanks,
>> Can Guo.
>>
>> >> &dev_info->model, SD_ASCII_STD);
Hi Stanley,
FYI, the default values in bRefClkGatingWaitTime from vendors are around
50 - 100.
I agree with you. I will just remove the extra delay here and let's
handle it in our own platform drivers.
Thanks,
Can Guo.
next prev parent reply other threads:[~2020-02-06 2:40 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1580721472-10784-1-git-send-email-cang@codeaurora.org>
2020-02-03 9:17 ` [PATCH v5 1/8] scsi: ufs: Flush exception event before suspend Can Guo
2020-02-03 21:31 ` [EXT] " Bean Huo (beanhuo)
2020-02-03 9:17 ` [PATCH v5 2/8] scsi: ufs: set load before setting voltage in regulators Can Guo
2020-02-03 21:41 ` [EXT] " Bean Huo (beanhuo)
2020-02-04 6:16 ` Stanley Chu
2020-02-03 9:17 ` [PATCH v5 3/8] scsi: ufs: Remove the check before call setup clock notify vops Can Guo
2020-02-03 22:14 ` [EXT] " Bean Huo (beanhuo)
2020-02-04 6:16 ` Stanley Chu
2020-02-03 9:17 ` [PATCH v5 4/8] scsi: ufs-qcom: Adjust bus bandwidth voting and unvoting Can Guo
2020-02-05 2:17 ` Asutosh Das (asd)
2020-02-03 9:17 ` [PATCH v5 5/8] scsi: ufs: Fix ufshcd_hold() caused scheduling while atomic Can Guo
2020-02-03 22:07 ` [EXT] " Bean Huo (beanhuo)
2020-02-04 6:26 ` Stanley Chu
2020-02-03 9:17 ` [PATCH v5 6/8] scsi: ufs: Add dev ref clock gating wait time support Can Guo
2020-02-04 15:26 ` [EXT] " Bean Huo (beanhuo)
2020-02-05 2:50 ` Stanley Chu
2020-02-05 4:52 ` Can Guo
2020-02-06 0:55 ` Stanley Chu
2020-02-06 2:39 ` Can Guo [this message]
2020-02-03 9:17 ` [PATCH v5 7/8] scsi: ufs-qcom: Delay specific time before gate ref clk Can Guo
2020-02-05 7:20 ` hongwus
2020-02-03 9:17 ` [PATCH v5 8/8] scsi: ufs: Select INITIAL adapt for HS Gear4 Can Guo
2020-02-04 15:26 ` [EXT] " Bean Huo (beanhuo)
2020-02-05 7:38 ` hongwus
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