> 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@xxxxxxxxxxx>
> > ---
> > 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.
I want to keep sending NOP_OUT commands repeatedly to get a response
from the UFS device, as per the existing method. To accommodate this method,
I propose increasing the total timeout duration by increasing the single timeout
value(defined by NOP_OUT_TIMEOUT) from 50ms to 100ms rather than
increasing the timeout value(defined by NOP_OUT_TIMEOUT) from 50ms to 1000ms
or increasing the retry count value(defined by NOP_OUT_RETRIES).
This is time measurement log confirmed on a real device with NOP_OUT_TIMEOUT is 100ms
1. normal operation
[ 2.010156] [6: kworker/u18:0: 76] ufshcd-qcom 1d84000.ufshc: [TEST] ufshcd_verify_dev_init: takes 1271 us, retries = 1 * 100ms.
2. issued log : exceeds 500ms
[ 2.524525] [6: kworker/u17:2: 141] ufshcd-qcom 1d84000.ufshc: [TEST] ufshcd_verify_dev_init: takes 533000 us, retries = 6 * 100ms.
And a certain UFS vendor has confirmed that the response to NOP_OUT command
can be delayed by up to 540ms in certain circumstances on a specific model.
BR,
Thank you.
DooHyun Hwang.
