[PATCH 1/2] scsi: ufs: core: Disable the reset settle delay

[PATCH 1/2] scsi: ufs: core: Disable the reset settle delay

[Bart Van Assche]

Neither UFS host controllers nor UFS devices require a ten second delay
after a host reset or after a bus reset. Hence this patch.

Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
 drivers/ufs/core/ufshcd.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 172d25fef740..ce7b765aa2af 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -8744,6 +8744,7 @@ static struct scsi_host_template ufshcd_driver_template = {
 	.max_sectors		= (1 << 20) / SECTOR_SIZE, /* 1 MiB */
 	.max_host_blocked	= 1,
 	.track_queue_depth	= 1,
+	.skip_settle_delay	= 1,
 	.sdev_groups		= ufshcd_driver_groups,
 	.rpm_autosuspend_delay	= RPM_AUTOSUSPEND_DELAY_MS,
 };

Re: [PATCH 1/2] scsi: ufs: core: Disable the reset settle delay

[Adrian Hunter]

On 14/03/23 22:58, Bart Van Assche wrote:
> Neither UFS host controllers nor UFS devices require a ten second delay
> after a host reset or after a bus reset. Hence this patch.
> 
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>

Acked-by: Adrian Hunter <adrian.hunter@intel.com>

> ---
>  drivers/ufs/core/ufshcd.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
> index 172d25fef740..ce7b765aa2af 100644
> --- a/drivers/ufs/core/ufshcd.c
> +++ b/drivers/ufs/core/ufshcd.c
> @@ -8744,6 +8744,7 @@ static struct scsi_host_template ufshcd_driver_template = {
>  	.max_sectors		= (1 << 20) / SECTOR_SIZE, /* 1 MiB */
>  	.max_host_blocked	= 1,
>  	.track_queue_depth	= 1,
> +	.skip_settle_delay	= 1,
>  	.sdev_groups		= ufshcd_driver_groups,
>  	.rpm_autosuspend_delay	= RPM_AUTOSUSPEND_DELAY_MS,
>  };

RE: [PATCH 1/2] scsi: ufs: core: Disable the reset settle delay

[Avri Altman]

> 
> Neither UFS host controllers nor UFS devices require a ten second delay
> after a host reset or after a bus reset. Hence this patch.
Bus reset handler is not implemented for ufs.

Thanks,
Avri

> 
> Signed-off-by: Bart Van Assche <bvanassche@acm.org>
> ---
>  drivers/ufs/core/ufshcd.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
> index 172d25fef740..ce7b765aa2af 100644
> --- a/drivers/ufs/core/ufshcd.c
> +++ b/drivers/ufs/core/ufshcd.c
> @@ -8744,6 +8744,7 @@ static struct scsi_host_template
> ufshcd_driver_template = {
>         .max_sectors            = (1 << 20) / SECTOR_SIZE, /* 1 MiB */
>         .max_host_blocked       = 1,
>         .track_queue_depth      = 1,
> +       .skip_settle_delay      = 1,
>         .sdev_groups            = ufshcd_driver_groups,
>         .rpm_autosuspend_delay  = RPM_AUTOSUSPEND_DELAY_MS,
>  };

Re: [PATCH 1/2] scsi: ufs: core: Disable the reset settle delay

[Bart Van Assche]

On 3/15/23 06:43, Avri Altman wrote:
>> Neither UFS host controllers nor UFS devices require a ten second delay
>> after a host reset or after a bus reset. Hence this patch.
>
> Bus reset handler is not implemented for ufs.

Hi Avri,

Do you perhaps want me to remove the reference to "bus reset" from the 
patch description?

Thanks,

Bart.

RE: [PATCH 1/2] scsi: ufs: core: Disable the reset settle delay

[Avri Altman]

> On 3/15/23 06:43, Avri Altman wrote:
> >> Neither UFS host controllers nor UFS devices require a ten second delay
> >> after a host reset or after a bus reset. Hence this patch.
> >
> > Bus reset handler is not implemented for ufs.
> 
> Hi Avri,
> 
> Do you perhaps want me to remove the reference to "bus reset" from the
> patch description?
Yes - this what I meant.

But aren’t we calling now scsi_report_bus_reset too soon?

Thanks,
Avri 

> 
> Thanks,
> 
> Bart.

Re: [PATCH 1/2] scsi: ufs: core: Disable the reset settle delay

[Bart Van Assche]

On 3/15/23 15:13, Avri Altman wrote:
> But aren’t we calling now scsi_report_bus_reset too soon?

Hi Avri,

I think that calling scsi_report_bus_reset() immediately after a host 
reset has finished is fine. My understanding is that the purpose of the 
reset settle delay is to prevent that commands get submitted to a SCSI 
device while it is not responsive. I'm not aware of a need to wait after 
a host reset has been submitted to a UFS device?

Thanks,

Bart.

RE: [PATCH 1/2] scsi: ufs: core: Disable the reset settle delay

[Avri Altman]

> On 3/15/23 15:13, Avri Altman wrote:
> > But aren’t we calling now scsi_report_bus_reset too soon?
> 
> Hi Avri,
> 
> I think that calling scsi_report_bus_reset() immediately after a host reset has
> finished is fine. My understanding is that the purpose of the reset settle delay
> is to prevent that commands get submitted to a SCSI device while it is not
> responsive. I'm not aware of a need to wait after a host reset has been
> submitted to a UFS device?
OK. Thanks.

Avri

> 
> Thanks,
> 
> Bart.

Re: [PATCH 1/2] scsi: ufs: core: Disable the reset settle delay

[Martin K. Petersen]

Bart,

> Neither UFS host controllers nor UFS devices require a ten second delay
> after a host reset or after a bus reset. Hence this patch.

Applied to 6.4/scsi-staging, thanks!

-- 
Martin K. Petersen	Oracle Linux Engineering

Re: [PATCH 1/2] scsi: ufs: core: Disable the reset settle delay

[Martin K. Petersen]

On Tue, 14 Mar 2023 13:58:12 -0700, Bart Van Assche wrote:

> Neither UFS host controllers nor UFS devices require a ten second delay
> after a host reset or after a bus reset. Hence this patch.
> 
> 

Applied to 6.4/scsi-queue, thanks!

[1/2] scsi: ufs: core: Disable the reset settle delay
      https://git.kernel.org/mkp/scsi/c/fb5ea4f5202b

-- 
Martin K. Petersen	Oracle Linux Engineering