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* [PATCH] drm/i915: Perf_limit_reasons are only available for Gen11+
@ 2022-09-19 16:24 Ashutosh Dixit
  2022-09-20 21:29 ` Rodrigo Vivi
  2022-09-28 11:38 ` [Intel-gfx] " Jani Nikula
  0 siblings, 2 replies; 6+ messages in thread
From: Ashutosh Dixit @ 2022-09-19 16:24 UTC (permalink / raw)
  To: intel-gfx; +Cc: Tilak Tangudu, Sujaritha Sundaresan, dri-devel, Rodrigo Vivi

Register GT0_PERF_LIMIT_REASONS (0x1381a8) is available only for
Gen11+. Therefore ensure perf_limit_reasons sysfs/debugfs files are created
only for Gen11+. Otherwise on Gen < 5 accessing these files results in the
following oops:

<1> [88.829420] BUG: unable to handle page fault for address: ffffc90000bb81a8
<1> [88.829438] #PF: supervisor read access in kernel mode
<1> [88.829447] #PF: error_code(0x0000) - not-present page

Bspec: 20008
Bug: https://gitlab.freedesktop.org/drm/intel/-/issues/6863
Fixes: fe5979665f64 ("drm/i915/debugfs: Add perf_limit_reasons in debugfs")
Fixes: fa68bff7cf27 ("drm/i915/gt: Add sysfs throttle frequency interfaces")
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
---
 drivers/gpu/drm/i915/gt/intel_gt.c            |  4 ++++
 drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c | 10 +++++++++-
 drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c   | 15 +++++++++++----
 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c
index 5ddae95d4886..b367cfff48d5 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt.c
@@ -233,6 +233,10 @@ static void gen6_clear_engine_error_register(struct intel_engine_cs *engine)
 
 i915_reg_t intel_gt_perf_limit_reasons_reg(struct intel_gt *gt)
 {
+	/* GT0_PERF_LIMIT_REASONS is available only for Gen11+ */
+	if (GRAPHICS_VER(gt->i915) < 11)
+		return INVALID_MMIO_REG;
+
 	return gt->type == GT_MEDIA ?
 		MTL_MEDIA_PERF_LIMIT_REASONS : GT0_PERF_LIMIT_REASONS;
 }
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c b/drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c
index 68310881a793..10f680dbd7b6 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c
@@ -682,6 +682,14 @@ static int perf_limit_reasons_clear(void *data, u64 val)
 
 	return 0;
 }
+
+static bool perf_limit_reasons_eval(void *data)
+{
+	struct intel_gt *gt = data;
+
+	return i915_mmio_reg_valid(intel_gt_perf_limit_reasons_reg(gt));
+}
+
 DEFINE_SIMPLE_ATTRIBUTE(perf_limit_reasons_fops, perf_limit_reasons_get,
 			perf_limit_reasons_clear, "%llu\n");
 
@@ -694,7 +702,7 @@ void intel_gt_pm_debugfs_register(struct intel_gt *gt, struct dentry *root)
 		{ "forcewake_user", &forcewake_user_fops, NULL},
 		{ "llc", &llc_fops, llc_eval },
 		{ "rps_boost", &rps_boost_fops, rps_eval },
-		{ "perf_limit_reasons", &perf_limit_reasons_fops, NULL },
+		{ "perf_limit_reasons", &perf_limit_reasons_fops, perf_limit_reasons_eval },
 	};
 
 	intel_gt_debugfs_register_files(root, files, ARRAY_SIZE(files), gt);
diff --git a/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c
index 54deae45d81f..904160952369 100644
--- a/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c
+++ b/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c
@@ -545,8 +545,7 @@ static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_ratl, RATL_MASK);
 static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_vr_thermalert, VR_THERMALERT_MASK);
 static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_vr_tdc, VR_TDC_MASK);
 
-static const struct attribute *freq_attrs[] = {
-	&dev_attr_punit_req_freq_mhz.attr,
+static const struct attribute *throttle_reason_attrs[] = {
 	&attr_throttle_reason_status.attr,
 	&attr_throttle_reason_pl1.attr,
 	&attr_throttle_reason_pl2.attr,
@@ -791,12 +790,20 @@ void intel_gt_sysfs_pm_init(struct intel_gt *gt, struct kobject *kobj)
 	if (!is_object_gt(kobj))
 		return;
 
-	ret = sysfs_create_files(kobj, freq_attrs);
+	ret = sysfs_create_file(kobj, &dev_attr_punit_req_freq_mhz.attr);
 	if (ret)
 		drm_warn(&gt->i915->drm,
-			 "failed to create gt%u throttle sysfs files (%pe)",
+			 "failed to create gt%u punit_req_freq_mhz sysfs (%pe)",
 			 gt->info.id, ERR_PTR(ret));
 
+	if (i915_mmio_reg_valid(intel_gt_perf_limit_reasons_reg(gt))) {
+		ret = sysfs_create_files(kobj, throttle_reason_attrs);
+		if (ret)
+			drm_warn(&gt->i915->drm,
+				 "failed to create gt%u throttle sysfs files (%pe)",
+				 gt->info.id, ERR_PTR(ret));
+	}
+
 	if (HAS_MEDIA_RATIO_MODE(gt->i915) && intel_uc_uses_guc_slpc(&gt->uc)) {
 		ret = sysfs_create_files(kobj, media_perf_power_attrs);
 		if (ret)
-- 
2.34.1


^ permalink raw reply related	[flat|nested] 6+ messages in thread
* Re: [PATCH] drm/i915: Perf_limit_reasons are only available for Gen11+
  2022-09-19 16:24 [PATCH] drm/i915: Perf_limit_reasons are only available for Gen11+ Ashutosh Dixit
@ 2022-09-20 21:29 ` Rodrigo Vivi
  2022-09-28 11:38 ` [Intel-gfx] " Jani Nikula
  1 sibling, 0 replies; 6+ messages in thread
From: Rodrigo Vivi @ 2022-09-20 21:29 UTC (permalink / raw)
  To: Ashutosh Dixit; +Cc: intel-gfx, Tilak Tangudu, Sujaritha Sundaresan, dri-devel

On Mon, Sep 19, 2022 at 09:24:01AM -0700, Ashutosh Dixit wrote:
> Register GT0_PERF_LIMIT_REASONS (0x1381a8) is available only for
> Gen11+. Therefore ensure perf_limit_reasons sysfs/debugfs files are created
> only for Gen11+. Otherwise on Gen < 5 accessing these files results in the
> following oops:
> 
> <1> [88.829420] BUG: unable to handle page fault for address: ffffc90000bb81a8
> <1> [88.829438] #PF: supervisor read access in kernel mode
> <1> [88.829447] #PF: error_code(0x0000) - not-present page
> 
> Bspec: 20008
> Bug: https://gitlab.freedesktop.org/drm/intel/-/issues/6863
> Fixes: fe5979665f64 ("drm/i915/debugfs: Add perf_limit_reasons in debugfs")
> Fixes: fa68bff7cf27 ("drm/i915/gt: Add sysfs throttle frequency interfaces")
> Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>

Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> ---
>  drivers/gpu/drm/i915/gt/intel_gt.c            |  4 ++++
>  drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c | 10 +++++++++-
>  drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c   | 15 +++++++++++----
>  3 files changed, 24 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c
> index 5ddae95d4886..b367cfff48d5 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt.c
> @@ -233,6 +233,10 @@ static void gen6_clear_engine_error_register(struct intel_engine_cs *engine)
>  
>  i915_reg_t intel_gt_perf_limit_reasons_reg(struct intel_gt *gt)
>  {
> +	/* GT0_PERF_LIMIT_REASONS is available only for Gen11+ */
> +	if (GRAPHICS_VER(gt->i915) < 11)
> +		return INVALID_MMIO_REG;
> +
>  	return gt->type == GT_MEDIA ?
>  		MTL_MEDIA_PERF_LIMIT_REASONS : GT0_PERF_LIMIT_REASONS;
>  }
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c b/drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c
> index 68310881a793..10f680dbd7b6 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c
> @@ -682,6 +682,14 @@ static int perf_limit_reasons_clear(void *data, u64 val)
>  
>  	return 0;
>  }
> +
> +static bool perf_limit_reasons_eval(void *data)
> +{
> +	struct intel_gt *gt = data;
> +
> +	return i915_mmio_reg_valid(intel_gt_perf_limit_reasons_reg(gt));
> +}
> +
>  DEFINE_SIMPLE_ATTRIBUTE(perf_limit_reasons_fops, perf_limit_reasons_get,
>  			perf_limit_reasons_clear, "%llu\n");
>  
> @@ -694,7 +702,7 @@ void intel_gt_pm_debugfs_register(struct intel_gt *gt, struct dentry *root)
>  		{ "forcewake_user", &forcewake_user_fops, NULL},
>  		{ "llc", &llc_fops, llc_eval },
>  		{ "rps_boost", &rps_boost_fops, rps_eval },
> -		{ "perf_limit_reasons", &perf_limit_reasons_fops, NULL },
> +		{ "perf_limit_reasons", &perf_limit_reasons_fops, perf_limit_reasons_eval },
>  	};
>  
>  	intel_gt_debugfs_register_files(root, files, ARRAY_SIZE(files), gt);
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c
> index 54deae45d81f..904160952369 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c
> @@ -545,8 +545,7 @@ static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_ratl, RATL_MASK);
>  static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_vr_thermalert, VR_THERMALERT_MASK);
>  static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_vr_tdc, VR_TDC_MASK);
>  
> -static const struct attribute *freq_attrs[] = {
> -	&dev_attr_punit_req_freq_mhz.attr,
> +static const struct attribute *throttle_reason_attrs[] = {
>  	&attr_throttle_reason_status.attr,
>  	&attr_throttle_reason_pl1.attr,
>  	&attr_throttle_reason_pl2.attr,
> @@ -791,12 +790,20 @@ void intel_gt_sysfs_pm_init(struct intel_gt *gt, struct kobject *kobj)
>  	if (!is_object_gt(kobj))
>  		return;
>  
> -	ret = sysfs_create_files(kobj, freq_attrs);
> +	ret = sysfs_create_file(kobj, &dev_attr_punit_req_freq_mhz.attr);
>  	if (ret)
>  		drm_warn(&gt->i915->drm,
> -			 "failed to create gt%u throttle sysfs files (%pe)",
> +			 "failed to create gt%u punit_req_freq_mhz sysfs (%pe)",
>  			 gt->info.id, ERR_PTR(ret));
>  
> +	if (i915_mmio_reg_valid(intel_gt_perf_limit_reasons_reg(gt))) {
> +		ret = sysfs_create_files(kobj, throttle_reason_attrs);
> +		if (ret)
> +			drm_warn(&gt->i915->drm,
> +				 "failed to create gt%u throttle sysfs files (%pe)",
> +				 gt->info.id, ERR_PTR(ret));
> +	}
> +
>  	if (HAS_MEDIA_RATIO_MODE(gt->i915) && intel_uc_uses_guc_slpc(&gt->uc)) {
>  		ret = sysfs_create_files(kobj, media_perf_power_attrs);
>  		if (ret)
> -- 
> 2.34.1
> 

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [Intel-gfx] [PATCH] drm/i915: Perf_limit_reasons are only available for Gen11+
  2022-09-19 16:24 [PATCH] drm/i915: Perf_limit_reasons are only available for Gen11+ Ashutosh Dixit
  2022-09-20 21:29 ` Rodrigo Vivi
@ 2022-09-28 11:38 ` Jani Nikula
  2022-09-28 18:17   ` Dixit, Ashutosh
  1 sibling, 1 reply; 6+ messages in thread
From: Jani Nikula @ 2022-09-28 11:38 UTC (permalink / raw)
  To: Ashutosh Dixit, intel-gfx; +Cc: dri-devel, Rodrigo Vivi

On Mon, 19 Sep 2022, Ashutosh Dixit <ashutosh.dixit@intel.com> wrote:
> Register GT0_PERF_LIMIT_REASONS (0x1381a8) is available only for
> Gen11+. Therefore ensure perf_limit_reasons sysfs/debugfs files are created
> only for Gen11+. Otherwise on Gen < 5 accessing these files results in the
> following oops:
>
> <1> [88.829420] BUG: unable to handle page fault for address: ffffc90000bb81a8
> <1> [88.829438] #PF: supervisor read access in kernel mode
> <1> [88.829447] #PF: error_code(0x0000) - not-present page
>
> Bspec: 20008
> Bug: https://gitlab.freedesktop.org/drm/intel/-/issues/6863
> Fixes: fe5979665f64 ("drm/i915/debugfs: Add perf_limit_reasons in debugfs")
> Fixes: fa68bff7cf27 ("drm/i915/gt: Add sysfs throttle frequency interfaces")
> Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>

Ashutosh, can you provide a backport of this i.e. commit 0d2d201095e9
("drm/i915: Perf_limit_reasons are only available for Gen11+") that
applies cleanly on drm-intel-fixes, please?

BR,
Jani.


> ---
>  drivers/gpu/drm/i915/gt/intel_gt.c            |  4 ++++
>  drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c | 10 +++++++++-
>  drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c   | 15 +++++++++++----
>  3 files changed, 24 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt.c b/drivers/gpu/drm/i915/gt/intel_gt.c
> index 5ddae95d4886..b367cfff48d5 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt.c
> @@ -233,6 +233,10 @@ static void gen6_clear_engine_error_register(struct intel_engine_cs *engine)
>  
>  i915_reg_t intel_gt_perf_limit_reasons_reg(struct intel_gt *gt)
>  {
> +	/* GT0_PERF_LIMIT_REASONS is available only for Gen11+ */
> +	if (GRAPHICS_VER(gt->i915) < 11)
> +		return INVALID_MMIO_REG;
> +
>  	return gt->type == GT_MEDIA ?
>  		MTL_MEDIA_PERF_LIMIT_REASONS : GT0_PERF_LIMIT_REASONS;
>  }
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c b/drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c
> index 68310881a793..10f680dbd7b6 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_pm_debugfs.c
> @@ -682,6 +682,14 @@ static int perf_limit_reasons_clear(void *data, u64 val)
>  
>  	return 0;
>  }
> +
> +static bool perf_limit_reasons_eval(void *data)
> +{
> +	struct intel_gt *gt = data;
> +
> +	return i915_mmio_reg_valid(intel_gt_perf_limit_reasons_reg(gt));
> +}
> +
>  DEFINE_SIMPLE_ATTRIBUTE(perf_limit_reasons_fops, perf_limit_reasons_get,
>  			perf_limit_reasons_clear, "%llu\n");
>  
> @@ -694,7 +702,7 @@ void intel_gt_pm_debugfs_register(struct intel_gt *gt, struct dentry *root)
>  		{ "forcewake_user", &forcewake_user_fops, NULL},
>  		{ "llc", &llc_fops, llc_eval },
>  		{ "rps_boost", &rps_boost_fops, rps_eval },
> -		{ "perf_limit_reasons", &perf_limit_reasons_fops, NULL },
> +		{ "perf_limit_reasons", &perf_limit_reasons_fops, perf_limit_reasons_eval },
>  	};
>  
>  	intel_gt_debugfs_register_files(root, files, ARRAY_SIZE(files), gt);
> diff --git a/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c b/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c
> index 54deae45d81f..904160952369 100644
> --- a/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c
> +++ b/drivers/gpu/drm/i915/gt/intel_gt_sysfs_pm.c
> @@ -545,8 +545,7 @@ static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_ratl, RATL_MASK);
>  static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_vr_thermalert, VR_THERMALERT_MASK);
>  static INTEL_GT_RPS_BOOL_ATTR_RO(throttle_reason_vr_tdc, VR_TDC_MASK);
>  
> -static const struct attribute *freq_attrs[] = {
> -	&dev_attr_punit_req_freq_mhz.attr,
> +static const struct attribute *throttle_reason_attrs[] = {
>  	&attr_throttle_reason_status.attr,
>  	&attr_throttle_reason_pl1.attr,
>  	&attr_throttle_reason_pl2.attr,
> @@ -791,12 +790,20 @@ void intel_gt_sysfs_pm_init(struct intel_gt *gt, struct kobject *kobj)
>  	if (!is_object_gt(kobj))
>  		return;
>  
> -	ret = sysfs_create_files(kobj, freq_attrs);
> +	ret = sysfs_create_file(kobj, &dev_attr_punit_req_freq_mhz.attr);
>  	if (ret)
>  		drm_warn(&gt->i915->drm,
> -			 "failed to create gt%u throttle sysfs files (%pe)",
> +			 "failed to create gt%u punit_req_freq_mhz sysfs (%pe)",
>  			 gt->info.id, ERR_PTR(ret));
>  
> +	if (i915_mmio_reg_valid(intel_gt_perf_limit_reasons_reg(gt))) {
> +		ret = sysfs_create_files(kobj, throttle_reason_attrs);
> +		if (ret)
> +			drm_warn(&gt->i915->drm,
> +				 "failed to create gt%u throttle sysfs files (%pe)",
> +				 gt->info.id, ERR_PTR(ret));
> +	}
> +
>  	if (HAS_MEDIA_RATIO_MODE(gt->i915) && intel_uc_uses_guc_slpc(&gt->uc)) {
>  		ret = sysfs_create_files(kobj, media_perf_power_attrs);
>  		if (ret)

-- 
Jani Nikula, Intel Open Source Graphics Center

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [Intel-gfx] [PATCH] drm/i915: Perf_limit_reasons are only available for Gen11+
  2022-09-28 11:38 ` [Intel-gfx] " Jani Nikula
@ 2022-09-28 18:17   ` Dixit, Ashutosh
  2022-09-28 18:35     ` Rodrigo Vivi
  0 siblings, 1 reply; 6+ messages in thread
From: Dixit, Ashutosh @ 2022-09-28 18:17 UTC (permalink / raw)
  To: Jani Nikula; +Cc: intel-gfx, dri-devel, Rodrigo Vivi

On Wed, 28 Sep 2022 04:38:46 -0700, Jani Nikula wrote:
>
> On Mon, 19 Sep 2022, Ashutosh Dixit <ashutosh.dixit@intel.com> wrote:
> > Register GT0_PERF_LIMIT_REASONS (0x1381a8) is available only for
> > Gen11+. Therefore ensure perf_limit_reasons sysfs/debugfs files are created
> > only for Gen11+. Otherwise on Gen < 5 accessing these files results in the
> > following oops:
> >
> > <1> [88.829420] BUG: unable to handle page fault for address: ffffc90000bb81a8
> > <1> [88.829438] #PF: supervisor read access in kernel mode
> > <1> [88.829447] #PF: error_code(0x0000) - not-present page
> >
> > Bspec: 20008
> > Bug: https://gitlab.freedesktop.org/drm/intel/-/issues/6863
> > Fixes: fe5979665f64 ("drm/i915/debugfs: Add perf_limit_reasons in debugfs")
> > Fixes: fa68bff7cf27 ("drm/i915/gt: Add sysfs throttle frequency interfaces")
> > Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
>

Hi Jani,

> Ashutosh, can you provide a backport of this i.e. commit 0d2d201095e9
> ("drm/i915: Perf_limit_reasons are only available for Gen11+") that
> applies cleanly on drm-intel-fixes, please?

I've sent the patch:

https://patchwork.freedesktop.org/series/109196/

Not sure though if it is worth applying on drm-intel-fixes because of one
conflict with drm-tip which will need to be resolved manually. On
drm-intel-fixes the crash mentioned above will be seen only on Gen < 5 if
someone manually cat's the sysfs. We had to fix on drm-tip because there
was a CI failure with Gen3 debugfs but that code is not in drm-intel-fixes.

Thanks.
--
Ashutosh

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [Intel-gfx] [PATCH] drm/i915: Perf_limit_reasons are only available for Gen11+
  2022-09-28 18:17   ` Dixit, Ashutosh
@ 2022-09-28 18:35     ` Rodrigo Vivi
  2022-09-28 19:03       ` Dixit, Ashutosh
  0 siblings, 1 reply; 6+ messages in thread
From: Rodrigo Vivi @ 2022-09-28 18:35 UTC (permalink / raw)
  To: Dixit, Ashutosh; +Cc: intel-gfx, dri-devel

On Wed, Sep 28, 2022 at 11:17:06AM -0700, Dixit, Ashutosh wrote:
> On Wed, 28 Sep 2022 04:38:46 -0700, Jani Nikula wrote:
> >
> > On Mon, 19 Sep 2022, Ashutosh Dixit <ashutosh.dixit@intel.com> wrote:
> > > Register GT0_PERF_LIMIT_REASONS (0x1381a8) is available only for
> > > Gen11+. Therefore ensure perf_limit_reasons sysfs/debugfs files are created
> > > only for Gen11+. Otherwise on Gen < 5 accessing these files results in the
> > > following oops:
> > >
> > > <1> [88.829420] BUG: unable to handle page fault for address: ffffc90000bb81a8
> > > <1> [88.829438] #PF: supervisor read access in kernel mode
> > > <1> [88.829447] #PF: error_code(0x0000) - not-present page
> > >
> > > Bspec: 20008
> > > Bug: https://gitlab.freedesktop.org/drm/intel/-/issues/6863
> > > Fixes: fe5979665f64 ("drm/i915/debugfs: Add perf_limit_reasons in debugfs")
> > > Fixes: fa68bff7cf27 ("drm/i915/gt: Add sysfs throttle frequency interfaces")
> > > Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
> >
> 
> Hi Jani,
> 
> > Ashutosh, can you provide a backport of this i.e. commit 0d2d201095e9
> > ("drm/i915: Perf_limit_reasons are only available for Gen11+") that
> > applies cleanly on drm-intel-fixes, please?
> 
> I've sent the patch:
> 
> https://patchwork.freedesktop.org/series/109196/
> 
> Not sure though if it is worth applying on drm-intel-fixes because of one
> conflict with drm-tip which will need to be resolved manually. On

The conflict shouldn't be that bad to resolve, but since the patch deviates
from the original, the new commit message needs to highlight and explain
that this is a backport and the reasons of the difference and including the sha
of the already merged patch. Similar to the option 3 of the stable rules. [1].

Well, another option is to wait until this patch gets propagated to Linus master
and then send the backported version to the stable mailing list. But again,
with the proper rules of the option 3. [1]

[1] - https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html

> drm-intel-fixes the crash mentioned above will be seen only on Gen < 5 if
> someone manually cat's the sysfs. We had to fix on drm-tip because there
> was a CI failure with Gen3 debugfs but that code is not in drm-intel-fixes.

since it is sysfs it is probably a good protection to have anyway.

> 
> Thanks.
> --
> Ashutosh

^ permalink raw reply	[flat|nested] 6+ messages in thread
* Re: [Intel-gfx] [PATCH] drm/i915: Perf_limit_reasons are only available for Gen11+
  2022-09-28 18:35     ` Rodrigo Vivi
@ 2022-09-28 19:03       ` Dixit, Ashutosh
  0 siblings, 0 replies; 6+ messages in thread
From: Dixit, Ashutosh @ 2022-09-28 19:03 UTC (permalink / raw)
  To: Rodrigo Vivi; +Cc: intel-gfx, dri-devel

On Wed, 28 Sep 2022 11:35:18 -0700, Rodrigo Vivi wrote:
>
> On Wed, Sep 28, 2022 at 11:17:06AM -0700, Dixit, Ashutosh wrote:
> > On Wed, 28 Sep 2022 04:38:46 -0700, Jani Nikula wrote:
> > >
> > > On Mon, 19 Sep 2022, Ashutosh Dixit <ashutosh.dixit@intel.com> wrote:
> > > > Register GT0_PERF_LIMIT_REASONS (0x1381a8) is available only for
> > > > Gen11+. Therefore ensure perf_limit_reasons sysfs/debugfs files are created
> > > > only for Gen11+. Otherwise on Gen < 5 accessing these files results in the
> > > > following oops:
> > > >
> > > > <1> [88.829420] BUG: unable to handle page fault for address: ffffc90000bb81a8
> > > > <1> [88.829438] #PF: supervisor read access in kernel mode
> > > > <1> [88.829447] #PF: error_code(0x0000) - not-present page
> > > >
> > > > Bspec: 20008
> > > > Bug: https://gitlab.freedesktop.org/drm/intel/-/issues/6863
> > > > Fixes: fe5979665f64 ("drm/i915/debugfs: Add perf_limit_reasons in debugfs")
> > > > Fixes: fa68bff7cf27 ("drm/i915/gt: Add sysfs throttle frequency interfaces")
> > > > Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
> > >
> >
> > Hi Jani,
> >
> > > Ashutosh, can you provide a backport of this i.e. commit 0d2d201095e9
> > > ("drm/i915: Perf_limit_reasons are only available for Gen11+") that
> > > applies cleanly on drm-intel-fixes, please?
> >
> > I've sent the patch:
> >
> > https://patchwork.freedesktop.org/series/109196/
> >
> > Not sure though if it is worth applying on drm-intel-fixes because of one
> > conflict with drm-tip which will need to be resolved manually. On

Hi Rodrigo,

> The conflict shouldn't be that bad to resolve, but since the patch deviates
> from the original, the new commit message needs to highlight and explain
> that this is a backport and the reasons of the difference and including the sha
> of the already merged patch. Similar to the option 3 of the stable rules. [1].

I have improved the commit message and sent out a v2. Please take a look.

Thanks.
--
Ashutosh

> Well, another option is to wait until this patch gets propagated to Linus master
> and then send the backported version to the stable mailing list. But again,
> with the proper rules of the option 3. [1]
>
> [1] - https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
>
> > drm-intel-fixes the crash mentioned above will be seen only on Gen < 5 if
> > someone manually cat's the sysfs. We had to fix on drm-tip because there
> > was a CI failure with Gen3 debugfs but that code is not in drm-intel-fixes.
>
> since it is sysfs it is probably a good protection to have anyway.
>
> >
> > Thanks.
> > --
> > Ashutosh

^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2022-09-28 19:04 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-09-19 16:24 [PATCH] drm/i915: Perf_limit_reasons are only available for Gen11+ Ashutosh Dixit
2022-09-20 21:29 ` Rodrigo Vivi
2022-09-28 11:38 ` [Intel-gfx] " Jani Nikula
2022-09-28 18:17   ` Dixit, Ashutosh
2022-09-28 18:35     ` Rodrigo Vivi
2022-09-28 19:03       ` Dixit, Ashutosh

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