Re: [PATCH v3 5/5] Revert "scsi: ufs: disable vccq if it's not needed by UFS device"

[Jeffrey Hugo <jhugo@codeaurora.org>]

On 2/7/2019 1:50 AM, Alim Akhtar wrote:
> Hi Marc,
> 
> On 06/02/19 9:22 PM, Marc Gonzalez wrote:
>> On 06/02/2019 16:27, Alim Akhtar wrote:
>>
>>> On 06/02/19 8:29 PM, Marc Gonzalez wrote:
>>>
>>>> [    2.405734] regulator_disable: ENTER vdd_l26
>>>> [    2.405958] regulator_disable: EXIT vdd_l26
>>>> [    2.406032]   regulator_set_load: vdd_l26 = 0 uA
>>>> [    3.930447] ufshcd-qcom 1da4000.ufshc: ufshcd_query_attr: opcode 0x04 for idn 13 failed, index 0, err = -11
>>>> [    5.434358] ufshcd-qcom 1da4000.ufshc: ufshcd_query_attr: opcode 0x04 for idn 13 failed, index 0, err = -11
>>>> [    6.938318] ufshcd-qcom 1da4000.ufshc: ufshcd_query_attr: opcode 0x04 for idn 13 failed, index 0, err = -11
>>>> [    6.938414] ufshcd-qcom 1da4000.ufshc: ufshcd_query_attr_retry: query attribute, idn 13, failed with error -11 after 3 retires
>>>> [    6.946959] ufshcd-qcom 1da4000.ufshc: ufshcd_disable_auto_bkops: failed to enable exception event -11
>>>> [    6.958523] ufshcd-qcom 1da4000.ufshc: dme-peer-get: attr-id 0x1587 failed 3 retries
>>>> [    6.967730] ufshcd-qcom 1da4000.ufshc: dme-peer-get: attr-id 0x1586 failed 3 retries
>>>> [    6.975576] ufshcd-qcom 1da4000.ufshc: ufshcd_get_max_pwr_mode: invalid max pwm tx gear read = 0
>>>> [    6.983306] ufshcd-qcom 1da4000.ufshc: ufshcd_probe_hba: Failed getting max supported power mode
>>>> [    8.506314] ufshcd-qcom 1da4000.ufshc: ufshcd_query_flag: Sending flag query for idn 3 failed, err = -11
>>>> [   10.010352] ufshcd-qcom 1da4000.ufshc: ufshcd_query_flag: Sending flag query for idn 3 failed, err = -11
>>>> [   11.514313] ufshcd-qcom 1da4000.ufshc: ufshcd_query_flag: Sending flag query for idn 3 failed, err = -11
>>>> [   11.514412] ufshcd-qcom 1da4000.ufshc: ufshcd_query_flag_retry: query attribute, opcode 5, idn 3, failed with error -11 after 3 retires
>>>> [   13.050354] ufshcd-qcom 1da4000.ufshc: __ufshcd_query_descriptor: opcode 0x01 for idn 8 failed, index 0, err = -11
>>>> [   14.554313] ufshcd-qcom 1da4000.ufshc: __ufshcd_query_descriptor: opcode 0x01 for idn 8 failed, index 0, err = -11
>>>> [   16.058313] ufshcd-qcom 1da4000.ufshc: __ufshcd_query_descriptor: opcode 0x01 for idn 8 failed, index 0, err = -11
>>>> [   16.058421] ufshcd-qcom 1da4000.ufshc: ufshcd_read_desc_param: Failed reading descriptor. desc_id 8, desc_index 0, param_offset 0, ret -11
>>>> [   16.067654] ufshcd-qcom 1da4000.ufshc: ufshcd_init_icc_levels: Failed reading power descriptor.len = 98 ret = -11
>>>> [   37.074334] ufshcd-qcom 1da4000.ufshc: link startup failed 1
>>>
>>> Can you check if your UFS device RESET_N is asserted correctly. It might
>>> be connected to some regulator and may be you can try keeping that
>>> regulator as "regulator-always-on" from your DT node.
>>
>> How do I check RESET_N? In software or hardware?
>>
> RST_N is the reset logic for UFS device core logic and it is input to
> the device from UFS host controller.So, in your platform please check if
> this line somehow connected to (pulled up) a PMIC supply. If that is the
> case, please keep that regulator ON and see if this issue is resolved.

The reset line is routed though the global clock controller (GCC), and 
must be explicitly asserted within the GCC to trigger a reset.  As far 
as I am aware, Linux is not touching this.

Additionally, I fail to see how if this was a reset issue, reverting 
60f0187031c0 would have any impact (which doing so addresses our issue)

>> Do you think it is not a good idea to revert 60f0187031c05e04cbadffb62f557d0ff3564490 ?
>>
> Please hold on till we understand the real cause of this issue. Or we
> have a consensuses for reverting the said commit.
> Thanks!

Did you see https://lkml.org/lkml/2019/2/5/659 where I indicated VCCQ 
powers components within the host controller, and by not setting load on 
the regulator properly, we are likely undervolting those components due 
to the current draw?

-- 
Jeffrey Hugo
Qualcomm Datacenter Technologies as an affiliate of Qualcomm 
Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.