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

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Date:	Sun, 25 Oct 2015 13:38:19 -0000
From:	ygardi@...eaurora.org
To:	"Akinobu Mita" <akinobu.mita@...il.com>
Cc:	"Yaniv Gardi" <ygardi@...eaurora.org>,
	"Rob Herring" <robherring2@...il.com>,
	"Jej B" <james.bottomley@...senpartnership.com>,
	"Paul Bolle" <pebolle@...cali.nl>,
	"Christoph Hellwig" <hch@...radead.org>,
	"LKML" <linux-kernel@...r.kernel.org>,
	"linux-scsi@...r.kernel.org" <linux-scsi@...r.kernel.org>,
	linux-arm-msm@...r.kernel.org, "Santosh Y" <santoshsy@...il.com>,
	linux-scsi-owner@...r.kernel.org,
	"Subhash Jadavani" <subhashj@...eaurora.org>,
	"Gilad Broner" <gbroner@...eaurora.org>,
	"Dolev Raviv" <draviv@...eaurora.org>,
	"Vinayak Holikatti" <vinholikatti@...il.com>,
	"James E.J. Bottomley" <jbottomley@...n.com>
Subject: Re: [PATCH v3 05/15] scsi: ufs: increase fDeviceInit query response
 timeout

> 2015-09-02 19:13 GMT+09:00 Yaniv Gardi <ygardi@...eaurora.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@...eaurora.org>
>> Signed-off-by: Yaniv Gardi <ygardi@...eaurora.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
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
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>


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