Re: [EXT] Re: [PATCH v5 4/4] ufs: Simplify the clock scaling mechanism implementation

[Can Guo <cang@codeaurora.org>]

On 2019-11-15 00:11, Bart Van Assche wrote:
> On 11/13/19 8:03 AM, Bean Huo (beanhuo) wrote:
>> I think, you are asking for comment from Can.  As for me, attached 
>> patch is better.
>> Removing ufshcd_wait_for_doorbell_clr(), instead of reading doorbell 
>> register, Now
>> using block layer blk_mq_{un,}freeze_queue(), looks good. I tested 
>> your V5 patches,
>> didn't find problem yet.
>> 
>> Since my available platform doesn't support dynamic clk scaling, I 
>> think, now seems only
>> Qcom UFS controllers support this feature. So we need Can Guo to 
>> finally confirm it.
> 
> Hi Can,
> 
> Do you agree with this patch series if patch 4 is replaced by the
> patch attached to my previous e-mail? The entire (revised) series is
> available at https://github.com/bvanassche/linux/tree/ufs-for-next.
> 
> Thanks,
> 
> Bart.

Hi Bart,

After ufshcd_clock_scaling_prepare() returns(no error), all request 
queues are frozen. If failure
happens(say power mode change command fails) after this point and error 
handler kicks off,
we need to send dev commands(in ufshcd_probe_hba()) to bring UFS back to 
functionality.
However, as the hba->cmd_queue is frozen, dev commands cannot be sent, 
the error handler shall fail.

Thanks,

Can Guo.