Re: [PATCH v3 05/15] scsi: ufs: increase fDeviceInit query response timeout

[ygardi@codeaurora.org]

> 2015-09-02 19:13 GMT+09:00 Yaniv Gardi <ygardi@codeaurora.org>:
>> fDeviceInit query response time for some devices is too long that
>> default
>> query request timeout of 100ms may not be enough. Experiments show that
>> fDeviceInit response sometimes takes 500ms so to be on safer side this
>> change sets the timeout to 600ms. Without this change, we might
>> unnecessarily have to retry fDeviceInit query requests multiple times
>> and
>> each query request timeout prints one error message.
>>
>> Signed-off-by: Subhash Jadavani <subhashj@codeaurora.org>
>> Signed-off-by: Yaniv Gardi <ygardi@codeaurora.org>
>>
>> ---
>>  drivers/scsi/ufs/ufshcd.c | 12 +++++++++++-
>>  1 file changed, 11 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
>> index e0b8755..573a8cb 100644
>> --- a/drivers/scsi/ufs/ufshcd.c
>> +++ b/drivers/scsi/ufs/ufshcd.c
>> @@ -58,6 +58,12 @@
>>  #define QUERY_REQ_RETRIES 10
>>  /* Query request timeout */
>>  #define QUERY_REQ_TIMEOUT 30 /* msec */
>> +/*
>> + * Query request timeout for fDeviceInit flag
>> + * fDeviceInit query response time for some devices is too large that
>> default
>> + * QUERY_REQ_TIMEOUT may not be enough for such devices.
>> + */
>> +#define QUERY_FDEVICEINIT_REQ_TIMEOUT 600 /* msec */
>
> How about just increasing QUERY_REQ_TIMEOUT from 30ms to 600ms
> instead of conditionally setting timeout depending on ufs flag?

Your suggestion obviously could work (increasing the QUERY_REQ_TIMEOUT to
600ms), but in that case we bring extra delay of 570ms to error handling
of query timeout, and in such a case, instead of handling the error after
30ms we handle it after 600ms, which make the SW hang.
does it make sense ?


>
>>
>>  /* Task management command timeout */
>>  #define TM_CMD_TIMEOUT 100 /* msecs */
>> @@ -1651,6 +1657,7 @@ static int ufshcd_query_flag(struct ufs_hba *hba,
>> enum query_opcode opcode,
>>         struct ufs_query_req *request = NULL;
>>         struct ufs_query_res *response = NULL;
>>         int err, index = 0, selector = 0;
>> +       int timeout = QUERY_REQ_TIMEOUT;
>>
>>         BUG_ON(!hba);
>>
>> @@ -1683,7 +1690,10 @@ static int ufshcd_query_flag(struct ufs_hba *hba,
>> enum query_opcode opcode,
>>                 goto out_unlock;
>>         }
>>
>> -       err = ufshcd_exec_dev_cmd(hba, DEV_CMD_TYPE_QUERY,
>> QUERY_REQ_TIMEOUT);
>> +       if (idn == QUERY_FLAG_IDN_FDEVICEINIT)
>> +               timeout = QUERY_FDEVICEINIT_REQ_TIMEOUT;
>> +
>> +       err = ufshcd_exec_dev_cmd(hba, DEV_CMD_TYPE_QUERY, timeout);
>>
>>         if (err) {
>>                 dev_err(hba->dev,
>> --
>> 1.8.5.2
>>
>> --
>> QUALCOMM ISRAEL, on behalf of Qualcomm Innovation Center, Inc. is a
>> member of Code Aurora Forum, hosted by The Linux Foundation
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>