linux-arm-kernel.lists.infradead.org archive mirror
 help / color / mirror / Atom feed
* [PATCH v2] scsi: allow auto suspend override by low-level driver
@ 2019-09-12  6:35 Stanley Chu
  2019-09-12  6:35 ` [PATCH v2 1/3] scsi: core: " Stanley Chu
                   ` (2 more replies)
  0 siblings, 3 replies; 8+ messages in thread
From: Stanley Chu @ 2019-09-12  6:35 UTC (permalink / raw)
  To: linux-scsi, martin.petersen, avri.altman, alim.akhtar,
	pedrom.sousa, sthumma, jejb, bvanassche
  Cc: marc.w.gonzalez, andy.teng, chun-hung.wu, kuohong.wang, evgreen,
	subhashj, linux-mediatek, peter.wang, vivek.gautam, matthias.bgg,
	Stanley Chu, linux-arm-kernel, beanhuo

Until now the scsi mid-layer forbids runtime suspend till userspace
enables it. This is mainly to quarantine some disks with broken
runtime power management or have high latencies executing suspend
resume callbacks. If the userspace doesn't enable the runtime suspend
the underlying hardware will be always on even when it is not doing
any useful work and thus wasting power.

Some low-level drivers for the controllers can efficiently use runtime
power management to reduce power consumption and improve battery life.

This patchset allows runtime suspend parameters override within the LLD itself
instead of waiting for userspace to control the power management, and
make UFS as the first user of this capability.

v1 => v2:
- Allow "zero" sdev->rpm_autosuspend_delay (Avri)
- Fix format of some lines (Avri)

Stanley Chu (3):
  scsi: core: allow auto suspend override by low-level driver
  scsi: ufs: override auto suspend tunables for ufs
  scsi: ufs-mediatek: enable auto suspend capability

 drivers/scsi/scsi_scan.c        |  6 ++++++
 drivers/scsi/scsi_sysfs.c       |  3 ++-
 drivers/scsi/sd.c               |  4 ++++
 drivers/scsi/ufs/ufs-mediatek.c |  7 +++++++
 drivers/scsi/ufs/ufshcd.c       |  8 ++++++++
 drivers/scsi/ufs/ufshcd.h       | 10 ++++++++++
 include/scsi/scsi_device.h      |  2 +-
 7 files changed, 38 insertions(+), 2 deletions(-)

-- 
2.18.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH v2 1/3] scsi: core: allow auto suspend override by low-level driver
  2019-09-12  6:35 [PATCH v2] scsi: allow auto suspend override by low-level driver Stanley Chu
@ 2019-09-12  6:35 ` Stanley Chu
  2019-09-12 13:43   ` Bart Van Assche
  2019-09-12  6:35 ` [PATCH v2 2/3] scsi: ufs: override auto suspend tunables for ufs Stanley Chu
  2019-09-12  6:35 ` [PATCH v2 3/3] scsi: ufs-mediatek: enable auto suspend capability Stanley Chu
  2 siblings, 1 reply; 8+ messages in thread
From: Stanley Chu @ 2019-09-12  6:35 UTC (permalink / raw)
  To: linux-scsi, martin.petersen, avri.altman, alim.akhtar,
	pedrom.sousa, sthumma, jejb, bvanassche
  Cc: marc.w.gonzalez, andy.teng, chun-hung.wu, kuohong.wang, evgreen,
	subhashj, linux-mediatek, peter.wang, vivek.gautam, matthias.bgg,
	Stanley Chu, linux-arm-kernel, beanhuo

Rework from previous work by:
Sujit Reddy Thumma <sthumma@codeaurora.org>

Until now the scsi mid-layer forbids runtime suspend till userspace
enables it. This is mainly to quarantine some disks with broken
runtime power management or have high latencies executing suspend
resume callbacks. If the userspace doesn't enable the runtime suspend
the underlying hardware will be always on even when it is not doing
any useful work and thus wasting power.

Some low-level drivers for the controllers can efficiently use runtime
power management to reduce power consumption and improve battery life.
Allow runtime suspend parameters override within the LLD itself
instead of waiting for userspace to control the power management.

Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Reviewed-by: Avri Altman <avri.altman@wdc.com>
---
 drivers/scsi/scsi_scan.c   | 6 ++++++
 drivers/scsi/scsi_sysfs.c  | 3 ++-
 drivers/scsi/sd.c          | 4 ++++
 include/scsi/scsi_device.h | 2 +-
 4 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/scsi/scsi_scan.c b/drivers/scsi/scsi_scan.c
index 058079f915f1..caf700a6b7c8 100644
--- a/drivers/scsi/scsi_scan.c
+++ b/drivers/scsi/scsi_scan.c
@@ -280,6 +280,12 @@ static struct scsi_device *scsi_alloc_sdev(struct scsi_target *starget,
 	scsi_change_queue_depth(sdev, sdev->host->cmd_per_lun ?
 					sdev->host->cmd_per_lun : 1);
 
+	/*
+	 * Keep autosuspend disabled by default unless LLDD specifically
+	 * enables it in slave_configure.
+	 */
+	sdev->rpm_autosuspend_delay = -1;
+
 	scsi_sysfs_device_initialize(sdev);
 
 	if (shost->hostt->slave_alloc) {
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 64c96c7828ee..461aafadd208 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -1300,7 +1300,8 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev)
 	device_enable_async_suspend(&sdev->sdev_gendev);
 	scsi_autopm_get_target(starget);
 	pm_runtime_set_active(&sdev->sdev_gendev);
-	pm_runtime_forbid(&sdev->sdev_gendev);
+	if (sdev->rpm_autosuspend_delay < 0)
+		pm_runtime_forbid(&sdev->sdev_gendev);
 	pm_runtime_enable(&sdev->sdev_gendev);
 	scsi_autopm_put_target(starget);
 
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 149d406aacc9..de410b272158 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -3371,6 +3371,10 @@ static int sd_probe(struct device *dev)
 	}
 
 	blk_pm_runtime_init(sdp->request_queue, dev);
+	if (sdp->rpm_autosuspend_delay >= 0) {
+		pm_runtime_set_autosuspend_delay(dev,
+						 sdp->rpm_autosuspend_delay);
+	}
 	device_add_disk(dev, gd, NULL);
 	if (sdkp->capacity)
 		sd_dif_config_host(sdkp);
diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 202f4d6a4342..133b282fae5a 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -199,7 +199,7 @@ struct scsi_device {
 	unsigned broken_fua:1;		/* Don't set FUA bit */
 	unsigned lun_in_cdb:1;		/* Store LUN bits in CDB[1] */
 	unsigned unmap_limit_for_ws:1;	/* Use the UNMAP limit for WRITE SAME */
-
+	int rpm_autosuspend_delay;
 	atomic_t disk_events_disable_depth; /* disable depth for disk events */
 
 	DECLARE_BITMAP(supported_events, SDEV_EVT_MAXBITS); /* supported events */
-- 
2.18.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 8+ messages in thread

* [PATCH v2 2/3] scsi: ufs: override auto suspend tunables for ufs
  2019-09-12  6:35 [PATCH v2] scsi: allow auto suspend override by low-level driver Stanley Chu
  2019-09-12  6:35 ` [PATCH v2 1/3] scsi: core: " Stanley Chu
@ 2019-09-12  6:35 ` Stanley Chu
  2019-09-12  6:35 ` [PATCH v2 3/3] scsi: ufs-mediatek: enable auto suspend capability Stanley Chu
  2 siblings, 0 replies; 8+ messages in thread
From: Stanley Chu @ 2019-09-12  6:35 UTC (permalink / raw)
  To: linux-scsi, martin.petersen, avri.altman, alim.akhtar,
	pedrom.sousa, sthumma, jejb, bvanassche
  Cc: marc.w.gonzalez, andy.teng, chun-hung.wu, kuohong.wang, evgreen,
	subhashj, linux-mediatek, peter.wang, vivek.gautam, matthias.bgg,
	Stanley Chu, linux-arm-kernel, beanhuo

Rework from previous work by:
Sujit Reddy Thumma <sthumma@codeaurora.org>

Override auto suspend tunables for UFS device LUNs during
initialization so as to efficiently manage background operations
and the power consumption.

Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Reviewed-by: Avri Altman <avri.altman@wdc.com>
---
 drivers/scsi/ufs/ufshcd.c |  8 ++++++++
 drivers/scsi/ufs/ufshcd.h | 10 ++++++++++
 2 files changed, 18 insertions(+)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index 30b752c61b97..d253a018a73b 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -88,6 +88,9 @@
 /* Interrupt aggregation default timeout, unit: 40us */
 #define INT_AGGR_DEF_TO	0x02
 
+/* default delay of autosuspend: 2000 ms */
+#define RPM_AUTOSUSPEND_DELAY_MS 2000
+
 #define ufshcd_toggle_vreg(_dev, _vreg, _on)				\
 	({                                                              \
 		int _ret;                                               \
@@ -4612,9 +4615,14 @@ static int ufshcd_change_queue_depth(struct scsi_device *sdev, int depth)
  */
 static int ufshcd_slave_configure(struct scsi_device *sdev)
 {
+	struct ufs_hba *hba = shost_priv(sdev->host);
 	struct request_queue *q = sdev->request_queue;
 
 	blk_queue_update_dma_pad(q, PRDT_DATA_BYTE_COUNT_PAD - 1);
+
+	if (ufshcd_is_rpm_autosuspend_allowed(hba))
+		sdev->rpm_autosuspend_delay = RPM_AUTOSUSPEND_DELAY_MS;
+
 	return 0;
 }
 
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index a43c7135f33d..99ea416519af 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -714,6 +714,12 @@ struct ufs_hba {
 	 * the performance of ongoing read/write operations.
 	 */
 #define UFSHCD_CAP_KEEP_AUTO_BKOPS_ENABLED_EXCEPT_SUSPEND (1 << 5)
+	/*
+	 * This capability allows host controller driver to automatically
+	 * enable runtime power management by itself instead of waiting
+	 * for userspace to control the power management.
+	 */
+#define UFSHCD_CAP_RPM_AUTOSUSPEND (1 << 6)
 
 	struct devfreq *devfreq;
 	struct ufs_clk_scaling clk_scaling;
@@ -747,6 +753,10 @@ static inline bool ufshcd_can_autobkops_during_suspend(struct ufs_hba *hba)
 {
 	return hba->caps & UFSHCD_CAP_AUTO_BKOPS_SUSPEND;
 }
+static inline bool ufshcd_is_rpm_autosuspend_allowed(struct ufs_hba *hba)
+{
+	return hba->caps & UFSHCD_CAP_RPM_AUTOSUSPEND;
+}
 
 static inline bool ufshcd_is_intr_aggr_allowed(struct ufs_hba *hba)
 {
-- 
2.18.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 8+ messages in thread

* [PATCH v2 3/3] scsi: ufs-mediatek: enable auto suspend capability
  2019-09-12  6:35 [PATCH v2] scsi: allow auto suspend override by low-level driver Stanley Chu
  2019-09-12  6:35 ` [PATCH v2 1/3] scsi: core: " Stanley Chu
  2019-09-12  6:35 ` [PATCH v2 2/3] scsi: ufs: override auto suspend tunables for ufs Stanley Chu
@ 2019-09-12  6:35 ` Stanley Chu
  2019-09-12 13:46   ` Bart Van Assche
  2 siblings, 1 reply; 8+ messages in thread
From: Stanley Chu @ 2019-09-12  6:35 UTC (permalink / raw)
  To: linux-scsi, martin.petersen, avri.altman, alim.akhtar,
	pedrom.sousa, sthumma, jejb, bvanassche
  Cc: marc.w.gonzalez, andy.teng, chun-hung.wu, kuohong.wang, evgreen,
	subhashj, linux-mediatek, peter.wang, vivek.gautam, matthias.bgg,
	Stanley Chu, linux-arm-kernel, beanhuo

Enable auto suspend capability in MediaTek UFS driver.

Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Reviewed-by: Avri Altman <avri.altman@wdc.com>
---
 drivers/scsi/ufs/ufs-mediatek.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
index 0f6ff33ce52e..b7b177c6194c 100644
--- a/drivers/scsi/ufs/ufs-mediatek.c
+++ b/drivers/scsi/ufs/ufs-mediatek.c
@@ -117,6 +117,11 @@ static int ufs_mtk_setup_clocks(struct ufs_hba *hba, bool on,
 	return ret;
 }
 
+static void ufs_mtk_set_caps(struct ufs_hba *hba)
+{
+	hba->caps |= UFSHCD_CAP_RPM_AUTOSUSPEND;
+}
+
 /**
  * ufs_mtk_init - find other essential mmio bases
  * @hba: host controller instance
@@ -147,6 +152,8 @@ static int ufs_mtk_init(struct ufs_hba *hba)
 	if (err)
 		goto out_variant_clear;
 
+	ufs_mtk_set_caps(hba);
+
 	/*
 	 * ufshcd_vops_init() is invoked after
 	 * ufshcd_setup_clock(true) in ufshcd_hba_init() thus
-- 
2.18.0


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply related	[flat|nested] 8+ messages in thread

* Re: [PATCH v2 1/3] scsi: core: allow auto suspend override by low-level driver
  2019-09-12  6:35 ` [PATCH v2 1/3] scsi: core: " Stanley Chu
@ 2019-09-12 13:43   ` Bart Van Assche
  2019-09-16  6:38     ` Stanley Chu
  0 siblings, 1 reply; 8+ messages in thread
From: Bart Van Assche @ 2019-09-12 13:43 UTC (permalink / raw)
  To: Stanley Chu, linux-scsi, martin.petersen, avri.altman,
	alim.akhtar, pedrom.sousa, sthumma, jejb
  Cc: marc.w.gonzalez, andy.teng, chun-hung.wu, kuohong.wang, evgreen,
	subhashj, linux-mediatek, peter.wang, vivek.gautam, matthias.bgg,
	linux-arm-kernel, beanhuo

On 9/12/19 7:35 AM, Stanley Chu wrote:
> diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
> index 64c96c7828ee..461aafadd208 100644
> --- a/drivers/scsi/scsi_sysfs.c
> +++ b/drivers/scsi/scsi_sysfs.c
> @@ -1300,7 +1300,8 @@ int scsi_sysfs_add_sdev(struct scsi_device *sdev)
>  	device_enable_async_suspend(&sdev->sdev_gendev);
>  	scsi_autopm_get_target(starget);
>  	pm_runtime_set_active(&sdev->sdev_gendev);
> -	pm_runtime_forbid(&sdev->sdev_gendev);
> +	if (sdev->rpm_autosuspend_delay < 0)
> +		pm_runtime_forbid(&sdev->sdev_gendev);
>  	pm_runtime_enable(&sdev->sdev_gendev);
>  	scsi_autopm_put_target(starget);

So we have a single new struct member, rpm_autosuspend_delay, that
controls two different behaviors: (a) whether or not runtime suspend is
enabled at device creation time and (b) the power management autosuspend
delay. I don't like this. Should two separate variables be introduced
instead of using a single variable to control both behaviors?

> diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
> index 202f4d6a4342..133b282fae5a 100644
> --- a/include/scsi/scsi_device.h
> +++ b/include/scsi/scsi_device.h
> @@ -199,7 +199,7 @@ struct scsi_device {
>  	unsigned broken_fua:1;		/* Don't set FUA bit */
>  	unsigned lun_in_cdb:1;		/* Store LUN bits in CDB[1] */
>  	unsigned unmap_limit_for_ws:1;	/* Use the UNMAP limit for WRITE SAME */
> -
> +	int rpm_autosuspend_delay;
>  	atomic_t disk_events_disable_depth; /* disable depth for disk events */
>  
>  	DECLARE_BITMAP(supported_events, SDEV_EVT_MAXBITS); /* supported events */
> 

Since the default value for the autosuspend delay is the same for all
SCSI devices attached to a SCSI host is the same, please add a variable
with the same name in the SCSI host template and use that value as the
default value for SCSI devices. If the rpm_autosuspend_delay variable
only occurs in struct scsi_device then LLD authors are forced to
introduce a slave_configure function. Introducing such a function can be
avoided if the default autosuspend delay can be specified in the host
template.

Bart.


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH v2 3/3] scsi: ufs-mediatek: enable auto suspend capability
  2019-09-12  6:35 ` [PATCH v2 3/3] scsi: ufs-mediatek: enable auto suspend capability Stanley Chu
@ 2019-09-12 13:46   ` Bart Van Assche
  2019-09-16  6:29     ` Stanley Chu
  0 siblings, 1 reply; 8+ messages in thread
From: Bart Van Assche @ 2019-09-12 13:46 UTC (permalink / raw)
  To: Stanley Chu, linux-scsi, martin.petersen, avri.altman,
	alim.akhtar, pedrom.sousa, sthumma, jejb
  Cc: marc.w.gonzalez, andy.teng, chun-hung.wu, kuohong.wang, evgreen,
	subhashj, linux-mediatek, peter.wang, vivek.gautam, matthias.bgg,
	linux-arm-kernel, beanhuo

On 9/12/19 7:35 AM, Stanley Chu wrote:
> Enable auto suspend capability in MediaTek UFS driver.
> 
> Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
> Reviewed-by: Avri Altman <avri.altman@wdc.com>
> ---
>  drivers/scsi/ufs/ufs-mediatek.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/scsi/ufs/ufs-mediatek.c b/drivers/scsi/ufs/ufs-mediatek.c
> index 0f6ff33ce52e..b7b177c6194c 100644
> --- a/drivers/scsi/ufs/ufs-mediatek.c
> +++ b/drivers/scsi/ufs/ufs-mediatek.c
> @@ -117,6 +117,11 @@ static int ufs_mtk_setup_clocks(struct ufs_hba *hba, bool on,
>  	return ret;
>  }
>  
> +static void ufs_mtk_set_caps(struct ufs_hba *hba)
> +{
> +	hba->caps |= UFSHCD_CAP_RPM_AUTOSUSPEND;
> +}
> +
>  /**
>   * ufs_mtk_init - find other essential mmio bases
>   * @hba: host controller instance
> @@ -147,6 +152,8 @@ static int ufs_mtk_init(struct ufs_hba *hba)
>  	if (err)
>  		goto out_variant_clear;
>  
> +	ufs_mtk_set_caps(hba);
> +
>  	/*
>  	 * ufshcd_vops_init() is invoked after
>  	 * ufshcd_setup_clock(true) in ufshcd_hba_init() thus

Please inline the ufs_mtk_set_caps() function. Introducing single line
functions like is done in this patch doesn't improve readability.

Thanks,

Bart.


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH v2 3/3] scsi: ufs-mediatek: enable auto suspend capability
  2019-09-12 13:46   ` Bart Van Assche
@ 2019-09-16  6:29     ` Stanley Chu
  0 siblings, 0 replies; 8+ messages in thread
From: Stanley Chu @ 2019-09-16  6:29 UTC (permalink / raw)
  To: Bart Van Assche
  Cc: sthumma, linux-scsi, martin.petersen, marc.w.gonzalez,
	vivek.gautam, subhashj, jejb, chun-hung.wu, kuohong.wang,
	evgreen, avri.altman, linux-mediatek, peter.wang, alim.akhtar,
	andy.teng, matthias.bgg, pedrom.sousa, linux-arm-kernel, beanhuo

Hi Bart,


> > @@ -147,6 +152,8 @@ static int ufs_mtk_init(struct ufs_hba *hba)
> >  	if (err)
> >  		goto out_variant_clear;
> >  
> > +	ufs_mtk_set_caps(hba);
> > +
> >  	/*
> >  	 * ufshcd_vops_init() is invoked after
> >  	 * ufshcd_setup_clock(true) in ufshcd_hba_init() thus
> 
> Please inline the ufs_mtk_set_caps() function. Introducing single line
> functions like is done in this patch doesn't improve readability.
> 

OK! Will be fixed in next version.

Thanks,
Stanley



_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH v2 1/3] scsi: core: allow auto suspend override by low-level driver
  2019-09-12 13:43   ` Bart Van Assche
@ 2019-09-16  6:38     ` Stanley Chu
  0 siblings, 0 replies; 8+ messages in thread
From: Stanley Chu @ 2019-09-16  6:38 UTC (permalink / raw)
  To: Bart Van Assche
  Cc: sthumma, linux-scsi, martin.petersen, marc.w.gonzalez,
	vivek.gautam, subhashj, jejb,
	Chun-Hung Wu (巫駿宏),
	Kuohong Wang (王國鴻),
	evgreen, avri.altman, linux-mediatek,
	Peter Wang (王信友),
	alim.akhtar, Andy Teng (鄧如宏),
	matthias.bgg, pedrom.sousa, linux-arm-kernel, beanhuo

Hi Bart,

> > -	pm_runtime_forbid(&sdev->sdev_gendev);
> > +	if (sdev->rpm_autosuspend_delay < 0)
> > +		pm_runtime_forbid(&sdev->sdev_gendev);
> >  	pm_runtime_enable(&sdev->sdev_gendev);
> >  	scsi_autopm_put_target(starget);
> 
> So we have a single new struct member, rpm_autosuspend_delay, that
> controls two different behaviors: (a) whether or not runtime suspend is
> enabled at device creation time and (b) the power management autosuspend
> delay. I don't like this. Should two separate variables be introduced
> instead of using a single variable to control both behaviors?
> 

OK! Will try to separate different variables to control different things
in next version.

> > diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
> > index 202f4d6a4342..133b282fae5a 100644
> > --- a/include/scsi/scsi_device.h
> > +++ b/include/scsi/scsi_device.h
> > @@ -199,7 +199,7 @@ struct scsi_device {
> >  	unsigned broken_fua:1;		/* Don't set FUA bit */
> >  	unsigned lun_in_cdb:1;		/* Store LUN bits in CDB[1] */
> >  	unsigned unmap_limit_for_ws:1;	/* Use the UNMAP limit for WRITE SAME */
> > -
> > +	int rpm_autosuspend_delay;
> >  	atomic_t disk_events_disable_depth; /* disable depth for disk events */
> >  
> >  	DECLARE_BITMAP(supported_events, SDEV_EVT_MAXBITS); /* supported events */
> > 
> 
> Since the default value for the autosuspend delay is the same for all
> SCSI devices attached to a SCSI host is the same, please add a variable
> with the same name in the SCSI host template and use that value as the
> default value for SCSI devices. If the rpm_autosuspend_delay variable
> only occurs in struct scsi_device then LLD authors are forced to
> introduce a slave_configure function. Introducing such a function can be
> avoided if the default autosuspend delay can be specified in the host
> template.
> 

Sounds reasonable. Will create a member indicating autosuspend delay for
the same SCSI host in SCSI host template in next version.

> Bart.
> 

Thanks,
Stanley



_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2019-09-16  6:38 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-09-12  6:35 [PATCH v2] scsi: allow auto suspend override by low-level driver Stanley Chu
2019-09-12  6:35 ` [PATCH v2 1/3] scsi: core: " Stanley Chu
2019-09-12 13:43   ` Bart Van Assche
2019-09-16  6:38     ` Stanley Chu
2019-09-12  6:35 ` [PATCH v2 2/3] scsi: ufs: override auto suspend tunables for ufs Stanley Chu
2019-09-12  6:35 ` [PATCH v2 3/3] scsi: ufs-mediatek: enable auto suspend capability Stanley Chu
2019-09-12 13:46   ` Bart Van Assche
2019-09-16  6:29     ` Stanley Chu

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).