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SubjectRe: [PATCH v3 05/15] scsi: ufs: increase fDeviceInit query response timeout
From
2015-10-25 22:38 GMT+09:00  <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 ?

Compared to default scsi disk timeout (30s), 600ms does not look very
long. I was just worried that the code gets complicated if we need to
add yet another QUERY_XYZ_REQ_TIMEOUT macros when it turns out that
30ms timeout is not enough for other query requests under specific
conditions. But I don't too much care about it for now.

>>
>>>
>>> /* 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
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at http://vger.kernel.org/majordomo-info.html
>>
>
>


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