Messages in this thread |  | | Date | Thu, 06 Feb 2020 10:39:57 +0800 | From | Can Guo <> | Subject | Re: [PATCH v5 6/8] scsi: ufs: Add dev ref clock gating wait time support |
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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.
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