* [PATCH 1/2] drm/i915/pm: support disable SAGV via debugfs interface
@ 2021-02-21 14:59 Fino Meng
2021-02-23 7:28 ` Jan Kiszka
0 siblings, 1 reply; 4+ messages in thread
From: Fino Meng @ 2021-02-21 14:59 UTC (permalink / raw)
To: xenomai
SAGV (System Agent Geyserville) is part of the Enhanced Intel Speedstep
Technology. SAGV dynamically adjust the system agent's voltage and frequency
for power saving. SAGV's point change will cause DRAM's frequency change
accordingly, and DRAM is not accessible during the change. Disable SAGV will
tune the system more deterministic.
CAUTION: this debugfs interface is a work around operation, it doesn't
cope with any context state integrity of i915 driver.
Signed-off-by: Fino Meng <fino.meng@linux.intel.com>
---
drivers/gpu/drm/i915/i915_debugfs.c | 57 +++++++++++++++++++++++++++++
1 file changed, 57 insertions(+)
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index b0f51591f2e4..eefeb3994d1d 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -3725,6 +3725,62 @@ DEFINE_SIMPLE_ATTRIBUTE(i915_cache_sharing_fops,
i915_cache_sharing_get, i915_cache_sharing_set,
"%llu\n");
+static int
+i915_sagv_disable_set(void *data, u64 val)
+{
+ /* SAGV (System Agent Geyserville)'s offical name is System Agent
+ * Speedstep, it dynamically adjust the system agent's voltage
+ * and frequency for power saving. SAGV's point change will cause
+ * DRAM's frequency change accordingly, and DRAM is not accessible
+ * during the change. Disable SAGV will tune the system more
+ * deterministic. If SAGV already disabled by BIOS, then it's not
+ * possible to disable SAGV via send request to P-Unit mailbox.
+ *
+ * CAUTION: this debugfs interface is a work around operation,
+ * it doesn't cope with of the state integrity of i915.
+ *
+ * Ref:
+ * https://01.org/sites/default/files/documentation/
+ * intel-gfx-prm-osrc-kbl-vol12-display.pdf
+ */
+ struct drm_i915_private *dev_priv = data;
+
+ if (!(IS_GEN_RANGE(dev_priv, 6, 12)))
+ return -ENODEV;
+
+ if (val > 1)
+ return -EINVAL;
+
+ DRM_DEBUG_DRIVER("Manually request sagv disable: %llu\n", val);
+
+ if (val)
+ intel_disable_sagv(dev_priv);
+ else
+ intel_enable_sagv(dev_priv);
+
+ return 0;
+}
+
+static int
+i915_sagv_disable_get(void *data, u64 *val)
+{
+ struct drm_i915_private *dev_priv = data;
+
+ if (!(IS_GEN_RANGE(dev_priv, 6, 12)))
+ return -ENODEV;
+
+ if (dev_priv->sagv_status == I915_SAGV_DISABLED)
+ *val = 1;
+ else
+ *val = 0;
+
+ return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(i915_sagv_disable_fops,
+ i915_sagv_disable_get, i915_sagv_disable_set,
+ "%llu\n");
+
static void cherryview_sseu_device_status(struct drm_i915_private *dev_priv,
struct sseu_dev_info *sseu)
{
@@ -4341,6 +4397,7 @@ static const struct i915_debugfs_files {
} i915_debugfs_files[] = {
{"i915_wedged", &i915_wedged_fops},
{"i915_cache_sharing", &i915_cache_sharing_fops},
+ {"i915_sagv_disable", &i915_sagv_disable_fops},
{"i915_gem_drop_caches", &i915_drop_caches_fops},
#if IS_ENABLED(CONFIG_DRM_I915_CAPTURE_ERROR)
{"i915_error_state", &i915_error_state_fops},
--
2.20.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] drm/i915/pm: support disable SAGV via debugfs interface
2021-02-21 14:59 [PATCH 1/2] drm/i915/pm: support disable SAGV via debugfs interface Fino Meng
@ 2021-02-23 7:28 ` Jan Kiszka
2021-02-23 8:13 ` Fino Meng
0 siblings, 1 reply; 4+ messages in thread
From: Jan Kiszka @ 2021-02-23 7:28 UTC (permalink / raw)
To: Fino Meng, xenomai
On 21.02.21 15:59, Fino Meng via Xenomai wrote:
> SAGV (System Agent Geyserville) is part of the Enhanced Intel Speedstep
> Technology. SAGV dynamically adjust the system agent's voltage and frequency
> for power saving. SAGV's point change will cause DRAM's frequency change
> accordingly, and DRAM is not accessible during the change. Disable SAGV will
> tune the system more deterministic.
>
> CAUTION: this debugfs interface is a work around operation, it doesn't
> cope with any context state integrity of i915 driver.
>
> Signed-off-by: Fino Meng <fino.meng@linux.intel.com>
> ---
> drivers/gpu/drm/i915/i915_debugfs.c | 57 +++++++++++++++++++++++++++++
> 1 file changed, 57 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index b0f51591f2e4..eefeb3994d1d 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -3725,6 +3725,62 @@ DEFINE_SIMPLE_ATTRIBUTE(i915_cache_sharing_fops,
> i915_cache_sharing_get, i915_cache_sharing_set,
> "%llu\n");
>
> +static int
> +i915_sagv_disable_set(void *data, u64 val)
> +{
> + /* SAGV (System Agent Geyserville)'s offical name is System Agent
> + * Speedstep, it dynamically adjust the system agent's voltage
> + * and frequency for power saving. SAGV's point change will cause
> + * DRAM's frequency change accordingly, and DRAM is not accessible
> + * during the change. Disable SAGV will tune the system more
> + * deterministic. If SAGV already disabled by BIOS, then it's not
> + * possible to disable SAGV via send request to P-Unit mailbox.
> + *
> + * CAUTION: this debugfs interface is a work around operation,
> + * it doesn't cope with of the state integrity of i915.
> + *
> + * Ref:
> + * https://01.org/sites/default/files/documentation/
> + * intel-gfx-prm-osrc-kbl-vol12-display.pdf
> + */
> + struct drm_i915_private *dev_priv = data;
> +
> + if (!(IS_GEN_RANGE(dev_priv, 6, 12)))
> + return -ENODEV;
> +
> + if (val > 1)
> + return -EINVAL;
> +
> + DRM_DEBUG_DRIVER("Manually request sagv disable: %llu\n", val);
> +
> + if (val)
> + intel_disable_sagv(dev_priv);
> + else
> + intel_enable_sagv(dev_priv);
> +
> + return 0;
> +}
> +
> +static int
> +i915_sagv_disable_get(void *data, u64 *val)
> +{
> + struct drm_i915_private *dev_priv = data;
> +
> + if (!(IS_GEN_RANGE(dev_priv, 6, 12)))
> + return -ENODEV;
> +
> + if (dev_priv->sagv_status == I915_SAGV_DISABLED)
> + *val = 1;
> + else
> + *val = 0;
> +
> + return 0;
> +}
> +
> +DEFINE_SIMPLE_ATTRIBUTE(i915_sagv_disable_fops,
> + i915_sagv_disable_get, i915_sagv_disable_set,
> + "%llu\n");
> +
> static void cherryview_sseu_device_status(struct drm_i915_private *dev_priv,
> struct sseu_dev_info *sseu)
> {
> @@ -4341,6 +4397,7 @@ static const struct i915_debugfs_files {
> } i915_debugfs_files[] = {
> {"i915_wedged", &i915_wedged_fops},
> {"i915_cache_sharing", &i915_cache_sharing_fops},
> + {"i915_sagv_disable", &i915_sagv_disable_fops},
> {"i915_gem_drop_caches", &i915_drop_caches_fops},
> #if IS_ENABLED(CONFIG_DRM_I915_CAPTURE_ERROR)
> {"i915_error_state", &i915_error_state_fops},
>
Isn't such control of general interest to real-time community? How do we
deal with this side effect under PREEMPT-RT? Could we create something
that permits upstream integration?
Jan
--
Siemens AG, T RDA IOT
Corporate Competence Center Embedded Linux
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] drm/i915/pm: support disable SAGV via debugfs interface
2021-02-23 7:28 ` Jan Kiszka
@ 2021-02-23 8:13 ` Fino Meng
2021-02-23 8:49 ` Jan Kiszka
0 siblings, 1 reply; 4+ messages in thread
From: Fino Meng @ 2021-02-23 8:13 UTC (permalink / raw)
To: Jan Kiszka; +Cc: xenomai
Tue, Feb 23, 2021 at 08:28:32AM +0100, Jan Kiszka wrote:
> On 21.02.21 15:59, Fino Meng via Xenomai wrote:
> > SAGV (System Agent Geyserville) is part of the Enhanced Intel Speedstep
> > Technology. SAGV dynamically adjust the system agent's voltage and frequency
> > for power saving. SAGV's point change will cause DRAM's frequency change
> > accordingly, and DRAM is not accessible during the change. Disable SAGV will
> > tune the system more deterministic.
> >
> > CAUTION: this debugfs interface is a work around operation, it doesn't
> > cope with any context state integrity of i915 driver.
> >
> > Signed-off-by: Fino Meng <fino.meng@linux.intel.com>
> > ---
> > drivers/gpu/drm/i915/i915_debugfs.c | 57 +++++++++++++++++++++++++++++
> > 1 file changed, 57 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> > index b0f51591f2e4..eefeb3994d1d 100644
> > --- a/drivers/gpu/drm/i915/i915_debugfs.c
> > +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> > @@ -3725,6 +3725,62 @@ DEFINE_SIMPLE_ATTRIBUTE(i915_cache_sharing_fops,
> > i915_cache_sharing_get, i915_cache_sharing_set,
> > "%llu\n");
> >
> > +static int
> > +i915_sagv_disable_set(void *data, u64 val)
> > +{
> > + /* SAGV (System Agent Geyserville)'s offical name is System Agent
> > + * Speedstep, it dynamically adjust the system agent's voltage
> > + * and frequency for power saving. SAGV's point change will cause
> > + * DRAM's frequency change accordingly, and DRAM is not accessible
> > + * during the change. Disable SAGV will tune the system more
> > + * deterministic. If SAGV already disabled by BIOS, then it's not
> > + * possible to disable SAGV via send request to P-Unit mailbox.
> > + *
> > + * CAUTION: this debugfs interface is a work around operation,
> > + * it doesn't cope with of the state integrity of i915.
> > + *
> > + * Ref:
> > + * https://01.org/sites/default/files/documentation/
> > + * intel-gfx-prm-osrc-kbl-vol12-display.pdf
> > + */
> > + struct drm_i915_private *dev_priv = data;
> > +
> > + if (!(IS_GEN_RANGE(dev_priv, 6, 12)))
> > + return -ENODEV;
> > +
> > + if (val > 1)
> > + return -EINVAL;
> > +
> > + DRM_DEBUG_DRIVER("Manually request sagv disable: %llu\n", val);
> > +
> > + if (val)
> > + intel_disable_sagv(dev_priv);
> > + else
> > + intel_enable_sagv(dev_priv);
> > +
> > + return 0;
> > +}
> > +
> > +static int
> > +i915_sagv_disable_get(void *data, u64 *val)
> > +{
> > + struct drm_i915_private *dev_priv = data;
> > +
> > + if (!(IS_GEN_RANGE(dev_priv, 6, 12)))
> > + return -ENODEV;
> > +
> > + if (dev_priv->sagv_status == I915_SAGV_DISABLED)
> > + *val = 1;
> > + else
> > + *val = 0;
> > +
> > + return 0;
> > +}
> > +
> > +DEFINE_SIMPLE_ATTRIBUTE(i915_sagv_disable_fops,
> > + i915_sagv_disable_get, i915_sagv_disable_set,
> > + "%llu\n");
> > +
> > static void cherryview_sseu_device_status(struct drm_i915_private *dev_priv,
> > struct sseu_dev_info *sseu)
> > {
> > @@ -4341,6 +4397,7 @@ static const struct i915_debugfs_files {
> > } i915_debugfs_files[] = {
> > {"i915_wedged", &i915_wedged_fops},
> > {"i915_cache_sharing", &i915_cache_sharing_fops},
> > + {"i915_sagv_disable", &i915_sagv_disable_fops},
> > {"i915_gem_drop_caches", &i915_drop_caches_fops},
> > #if IS_ENABLED(CONFIG_DRM_I915_CAPTURE_ERROR)
> > {"i915_error_state", &i915_error_state_fops},
> >
>
> Isn't such control of general interest to real-time community? How do we
> deal with this side effect under PREEMPT-RT? Could we create something
> that permits upstream integration?
>
> Jan
>
> --
> Siemens AG, T RDA IOT
> Corporate Competence Center Embedded Linuxi
understand, I wrote to i915 developers but didn't get reply yet.
SAGV is missing on a lot of boards' BIOS, so I want to bring this WA to
community.
I would like to present a simple slice on tomorrow's Xenomai community
call, on our recent work of RT performance turing, use intel_idle,
intel_pstate, i915 drivers and kernel boot parameters,
BR/fino
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] drm/i915/pm: support disable SAGV via debugfs interface
2021-02-23 8:13 ` Fino Meng
@ 2021-02-23 8:49 ` Jan Kiszka
0 siblings, 0 replies; 4+ messages in thread
From: Jan Kiszka @ 2021-02-23 8:49 UTC (permalink / raw)
To: Fino Meng; +Cc: xenomai
On 23.02.21 09:13, Fino Meng wrote:
> Tue, Feb 23, 2021 at 08:28:32AM +0100, Jan Kiszka wrote:
>> On 21.02.21 15:59, Fino Meng via Xenomai wrote:
>>> SAGV (System Agent Geyserville) is part of the Enhanced Intel Speedstep
>>> Technology. SAGV dynamically adjust the system agent's voltage and frequency
>>> for power saving. SAGV's point change will cause DRAM's frequency change
>>> accordingly, and DRAM is not accessible during the change. Disable SAGV will
>>> tune the system more deterministic.
>>>
>>> CAUTION: this debugfs interface is a work around operation, it doesn't
>>> cope with any context state integrity of i915 driver.
>>>
>>> Signed-off-by: Fino Meng <fino.meng@linux.intel.com>
>>> ---
>>> drivers/gpu/drm/i915/i915_debugfs.c | 57 +++++++++++++++++++++++++++++
>>> 1 file changed, 57 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
>>> index b0f51591f2e4..eefeb3994d1d 100644
>>> --- a/drivers/gpu/drm/i915/i915_debugfs.c
>>> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
>>> @@ -3725,6 +3725,62 @@ DEFINE_SIMPLE_ATTRIBUTE(i915_cache_sharing_fops,
>>> i915_cache_sharing_get, i915_cache_sharing_set,
>>> "%llu\n");
>>>
>>> +static int
>>> +i915_sagv_disable_set(void *data, u64 val)
>>> +{
>>> + /* SAGV (System Agent Geyserville)'s offical name is System Agent
>>> + * Speedstep, it dynamically adjust the system agent's voltage
>>> + * and frequency for power saving. SAGV's point change will cause
>>> + * DRAM's frequency change accordingly, and DRAM is not accessible
>>> + * during the change. Disable SAGV will tune the system more
>>> + * deterministic. If SAGV already disabled by BIOS, then it's not
>>> + * possible to disable SAGV via send request to P-Unit mailbox.
>>> + *
>>> + * CAUTION: this debugfs interface is a work around operation,
>>> + * it doesn't cope with of the state integrity of i915.
>>> + *
>>> + * Ref:
>>> + * https://01.org/sites/default/files/documentation/
>>> + * intel-gfx-prm-osrc-kbl-vol12-display.pdf
>>> + */
>>> + struct drm_i915_private *dev_priv = data;
>>> +
>>> + if (!(IS_GEN_RANGE(dev_priv, 6, 12)))
>>> + return -ENODEV;
>>> +
>>> + if (val > 1)
>>> + return -EINVAL;
>>> +
>>> + DRM_DEBUG_DRIVER("Manually request sagv disable: %llu\n", val);
>>> +
>>> + if (val)
>>> + intel_disable_sagv(dev_priv);
>>> + else
>>> + intel_enable_sagv(dev_priv);
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int
>>> +i915_sagv_disable_get(void *data, u64 *val)
>>> +{
>>> + struct drm_i915_private *dev_priv = data;
>>> +
>>> + if (!(IS_GEN_RANGE(dev_priv, 6, 12)))
>>> + return -ENODEV;
>>> +
>>> + if (dev_priv->sagv_status == I915_SAGV_DISABLED)
>>> + *val = 1;
>>> + else
>>> + *val = 0;
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +DEFINE_SIMPLE_ATTRIBUTE(i915_sagv_disable_fops,
>>> + i915_sagv_disable_get, i915_sagv_disable_set,
>>> + "%llu\n");
>>> +
>>> static void cherryview_sseu_device_status(struct drm_i915_private *dev_priv,
>>> struct sseu_dev_info *sseu)
>>> {
>>> @@ -4341,6 +4397,7 @@ static const struct i915_debugfs_files {
>>> } i915_debugfs_files[] = {
>>> {"i915_wedged", &i915_wedged_fops},
>>> {"i915_cache_sharing", &i915_cache_sharing_fops},
>>> + {"i915_sagv_disable", &i915_sagv_disable_fops},
>>> {"i915_gem_drop_caches", &i915_drop_caches_fops},
>>> #if IS_ENABLED(CONFIG_DRM_I915_CAPTURE_ERROR)
>>> {"i915_error_state", &i915_error_state_fops},
>>>
>>
>> Isn't such control of general interest to real-time community? How do we
>> deal with this side effect under PREEMPT-RT? Could we create something
>> that permits upstream integration?
>>
>> Jan
>>
>> --
>> Siemens AG, T RDA IOT
>> Corporate Competence Center Embedded Linuxi
>
> understand, I wrote to i915 developers but didn't get reply yet.
> SAGV is missing on a lot of boards' BIOS, so I want to bring this WA to
> community.
> I would like to present a simple slice on tomorrow's Xenomai community
> call, on our recent work of RT performance turing, use intel_idle,
> intel_pstate, i915 drivers and kernel boot parameters,
>
OK, that would be helpful.
Thanks,
Jan
--
Siemens AG, T RDA IOT
Corporate Competence Center Embedded Linux
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2021-02-23 8:49 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-02-21 14:59 [PATCH 1/2] drm/i915/pm: support disable SAGV via debugfs interface Fino Meng
2021-02-23 7:28 ` Jan Kiszka
2021-02-23 8:13 ` Fino Meng
2021-02-23 8:49 ` Jan Kiszka
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.