Re: [PATCH] scsi: ufs: core: increase the NOP_OUT command timeout

[Bart Van Assche <bvanassche@acm.org>]

On 1/14/25 6:23 PM, DooHyun Hwang wrote:
> It is found that is UFS device may take longer than 500ms(50ms * 10times)
> to respond to NOP_OUT command.
> 
> The NOP_OUT command timeout was total 500ms that is from
> a timeout value of 50ms(defined by NOP_OUT_TIMEOUT)
> with 10 retries(defined by NOP_OUT_RETRIES)
> 
> This change increase the NOP_OUT command timeout to total 1000ms
> by changing timeout value to 100ms(NOP_OUT_TIMEOUT)
> 
> Signed-off-by: DooHyun Hwang <dh0421.hwang@samsung.com>
> ---
>   drivers/ufs/core/ufshcd.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
> index cd404ade48dc..bf5c4620ef6b 100644
> --- a/drivers/ufs/core/ufshcd.c
> +++ b/drivers/ufs/core/ufshcd.c
> @@ -57,8 +57,8 @@ enum {
>   };
>   /* NOP OUT retries waiting for NOP IN response */
>   #define NOP_OUT_RETRIES    10
> -/* Timeout after 50 msecs if NOP OUT hangs without response */
> -#define NOP_OUT_TIMEOUT    50 /* msecs */
> +/* Timeout after 100 msecs if NOP OUT hangs without response */
> +#define NOP_OUT_TIMEOUT    100 /* msecs */
>   
>   /* Query request retries */
>   #define QUERY_REQ_RETRIES 3

The above change relies on all device management commands being issued
with the same tag. If a single NOP OUT command may take longer than
500 ms, shouldn't NOP_OUT_TIMEOUT be increased to 1000 ms instead of
100 ms? The number of NOP OUT retries seems high to me and probably can
be reduced?

Thanks,

Bart.