diff mbox

[v4] drm/i915/chv: Set min freq to efficient frequency on chv

Message ID 1430276001-3454-1-git-send-email-deepak.s@linux.intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

deepak.s@linux.intel.com April 29, 2015, 2:53 a.m. UTC
From: Deepak S <deepak.s@linux.intel.com>

After feedback from the hardware team, now we set the GPU min/idel freq to RPe.
Punit is expecting us to operate GPU between Rpe & Rp0. If we drop the
frequency to RPn, punit is failing to change the input voltage to
minimum :(

Since Punit validates the rps range [RPe, RP0]. This patch
removes unused cherryview_rps_min_freq function.

v2: Change commit message

v3: set min_freq before idle_freq (chris)

v4: Squash 'Remove unused rps min function' patch

Signed-off-by: Deepak S <deepak.s@linux.intel.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/intel_pm.c | 21 ++-------------------
 1 file changed, 2 insertions(+), 19 deletions(-)

Comments

Ville Syrjälä April 29, 2015, 3:31 p.m. UTC | #1
On Wed, Apr 29, 2015 at 08:23:21AM +0530, deepak.s@linux.intel.com wrote:
> From: Deepak S <deepak.s@linux.intel.com>
> 
> After feedback from the hardware team, now we set the GPU min/idel freq to RPe.
> Punit is expecting us to operate GPU between Rpe & Rp0. If we drop the
> frequency to RPn, punit is failing to change the input voltage to
> minimum :(

So far I can't reproduce this problem on my BSW. In fact what I see
that the voltage at RPn is lower than the voltage at RPe, even while
we're in rc6.

without forcewake:
RPn -> 0x66
RPe -> 0x67
RP0 -> 0x69

with forcewake:
RPn -> 0x66
RPe -> 0x76
RP0 -> 0x9d

Also asking Punit to change the frequency after the GPU has gone to
rc6 does absolutely nothing (remind anyone of VLV?). I think I need to
retest my VLV C0 to see if my earlier observations there were accurate.
The shared Vnn rail does make it harder to observe this stuff on
VLV though.

So based on my tests this patch feels a bit wrong.

> 
> Since Punit validates the rps range [RPe, RP0]. This patch
> removes unused cherryview_rps_min_freq function.
> 
> v2: Change commit message
> 
> v3: set min_freq before idle_freq (chris)
> 
> v4: Squash 'Remove unused rps min function' patch
> 
> Signed-off-by: Deepak S <deepak.s@linux.intel.com>
> Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 21 ++-------------------
>  1 file changed, 2 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index a7516ed..78c89ff 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4715,24 +4715,6 @@ static int cherryview_rps_guar_freq(struct drm_i915_private *dev_priv)
>  	return rp1;
>  }
>  
> -static int cherryview_rps_min_freq(struct drm_i915_private *dev_priv)
> -{
> -	struct drm_device *dev = dev_priv->dev;
> -	u32 val, rpn;
> -
> -	if (dev->pdev->revision >= 0x20) {
> -		val = vlv_punit_read(dev_priv, FB_GFX_FMIN_AT_VMIN_FUSE);
> -		rpn = ((val >> FB_GFX_FMIN_AT_VMIN_FUSE_SHIFT) &
> -		       FB_GFX_FREQ_FUSE_MASK);
> -	} else { /* For pre-production hardware */
> -		val = vlv_punit_read(dev_priv, PUNIT_GPU_STATUS_REG);
> -		rpn = ((val >> PUNIT_GPU_STATIS_GFX_MIN_FREQ_SHIFT) &
> -		       PUNIT_GPU_STATUS_GFX_MIN_FREQ_MASK);
> -	}
> -
> -	return rpn;
> -}
> -
>  static int valleyview_rps_guar_freq(struct drm_i915_private *dev_priv)
>  {
>  	u32 val, rp1;
> @@ -4984,7 +4966,8 @@ static void cherryview_init_gt_powersave(struct drm_device *dev)
>  			 intel_gpu_freq(dev_priv, dev_priv->rps.rp1_freq),
>  			 dev_priv->rps.rp1_freq);
>  
> -	dev_priv->rps.min_freq = cherryview_rps_min_freq(dev_priv);
> +	/* PUnit validated range is only [RPe, RP0] */
> +	dev_priv->rps.min_freq = dev_priv->rps.efficient_freq;
>  	DRM_DEBUG_DRIVER("min GPU freq: %d MHz (%u)\n",
>  			 intel_gpu_freq(dev_priv, dev_priv->rps.min_freq),
>  			 dev_priv->rps.min_freq);
> -- 
> 1.9.1
Ville Syrjälä April 29, 2015, 7:53 p.m. UTC | #2
On Wed, Apr 29, 2015 at 06:31:56PM +0300, Ville Syrjälä wrote:
> On Wed, Apr 29, 2015 at 08:23:21AM +0530, deepak.s@linux.intel.com wrote:
> > From: Deepak S <deepak.s@linux.intel.com>
> > 
> > After feedback from the hardware team, now we set the GPU min/idel freq to RPe.
> > Punit is expecting us to operate GPU between Rpe & Rp0. If we drop the
> > frequency to RPn, punit is failing to change the input voltage to
> > minimum :(
> 
> So far I can't reproduce this problem on my BSW. In fact what I see
> that the voltage at RPn is lower than the voltage at RPe, even while
> we're in rc6.
> 
> without forcewake:
> RPn -> 0x66
> RPe -> 0x67
> RP0 -> 0x69
> 
> with forcewake:
> RPn -> 0x66
> RPe -> 0x76
> RP0 -> 0x9d
> 
> Also asking Punit to change the frequency after the GPU has gone to
> rc6 does absolutely nothing (remind anyone of VLV?). I think I need to
> retest my VLV C0 to see if my earlier observations there were accurate.
> The shared Vnn rail does make it harder to observe this stuff on
> VLV though.

I went back to my VLVs (had a B3 and C0 actually). And I'm seeing the
exact same behaviour on both, ie. requesting a new frequency from Punit
does nothing when the GPU is in rc6, and if I let it enter rc6 with a
high frequency Vnn also remains high. Previously I had thought that C0
fixed this, but now it definitely shows the same problem here. I must
have had some accidental forcewake somewhere when I originally tested
it,

So based on that, your other patch to remove the stepping check from
vlv_set_rps_idle() is in fact correct.

The question remains however what should we do with CHV. According to my
testing to get the minimum voltage we should keep RPn around, and we
should also do the vlv_set_rps_idle() workaround on CHV.

Oh and I also observed something else on VLV. Normally when entering rc6
the GPLL ref clock gets trunk gated at CCK (by Punit I assume). However
when using the vlv_gfx_clock_force() that doesn't happen. So I'm not
entirely sure the GPLL gets turned off properly in that case. Maybe we
should just use forcewake instead? Oh and BTW, CHV doesn't do the trunk
gating in either case. I'm not sure where to check if the GPLL is
actually running or not.

> 
> So based on my tests this patch feels a bit wrong.
> 
> > 
> > Since Punit validates the rps range [RPe, RP0]. This patch
> > removes unused cherryview_rps_min_freq function.
> > 
> > v2: Change commit message
> > 
> > v3: set min_freq before idle_freq (chris)
> > 
> > v4: Squash 'Remove unused rps min function' patch
> > 
> > Signed-off-by: Deepak S <deepak.s@linux.intel.com>
> > Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
> > ---
> >  drivers/gpu/drm/i915/intel_pm.c | 21 ++-------------------
> >  1 file changed, 2 insertions(+), 19 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > index a7516ed..78c89ff 100644
> > --- a/drivers/gpu/drm/i915/intel_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > @@ -4715,24 +4715,6 @@ static int cherryview_rps_guar_freq(struct drm_i915_private *dev_priv)
> >  	return rp1;
> >  }
> >  
> > -static int cherryview_rps_min_freq(struct drm_i915_private *dev_priv)
> > -{
> > -	struct drm_device *dev = dev_priv->dev;
> > -	u32 val, rpn;
> > -
> > -	if (dev->pdev->revision >= 0x20) {
> > -		val = vlv_punit_read(dev_priv, FB_GFX_FMIN_AT_VMIN_FUSE);
> > -		rpn = ((val >> FB_GFX_FMIN_AT_VMIN_FUSE_SHIFT) &
> > -		       FB_GFX_FREQ_FUSE_MASK);
> > -	} else { /* For pre-production hardware */
> > -		val = vlv_punit_read(dev_priv, PUNIT_GPU_STATUS_REG);
> > -		rpn = ((val >> PUNIT_GPU_STATIS_GFX_MIN_FREQ_SHIFT) &
> > -		       PUNIT_GPU_STATUS_GFX_MIN_FREQ_MASK);
> > -	}
> > -
> > -	return rpn;
> > -}
> > -
> >  static int valleyview_rps_guar_freq(struct drm_i915_private *dev_priv)
> >  {
> >  	u32 val, rp1;
> > @@ -4984,7 +4966,8 @@ static void cherryview_init_gt_powersave(struct drm_device *dev)
> >  			 intel_gpu_freq(dev_priv, dev_priv->rps.rp1_freq),
> >  			 dev_priv->rps.rp1_freq);
> >  
> > -	dev_priv->rps.min_freq = cherryview_rps_min_freq(dev_priv);
> > +	/* PUnit validated range is only [RPe, RP0] */
> > +	dev_priv->rps.min_freq = dev_priv->rps.efficient_freq;
> >  	DRM_DEBUG_DRIVER("min GPU freq: %d MHz (%u)\n",
> >  			 intel_gpu_freq(dev_priv, dev_priv->rps.min_freq),
> >  			 dev_priv->rps.min_freq);
> > -- 
> > 1.9.1
> 
> -- 
> Ville Syrjälä
> Intel OTC
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
Shuang He April 30, 2015, 2:42 a.m. UTC | #3
Tested-By: Intel Graphics QA PRTS (Patch Regression Test System Contact: shuang.he@intel.com)
Task id: 6282
-------------------------------------Summary-------------------------------------
Platform          Delta          drm-intel-nightly          Series Applied
PNV                                  276/276              276/276
ILK                                  302/302              302/302
SNB                                  316/316              316/316
IVB                 -1              264/264              263/264
BYT                 -4              227/227              223/227
BDW                 -1              318/318              317/318
-------------------------------------Detailed-------------------------------------
Platform  Test                                drm-intel-nightly          Series Applied
*IVB  igt@gem_storedw_batches_loop@normal      PASS(2)      FAIL(1)PASS(1)
*BYT  igt@gem_dummy_reloc_loop@render      FAIL(1)PASS(6)      TIMEOUT(1)PASS(1)
*BYT  igt@gem_exec_parse@bitmasks      FAIL(1)PASS(4)      DMESG_WARN(1)PASS(1)
(dmesg patch applied)drm:check_crtc_state[i915]]*ERROR*mismatch_in_has_infoframe(expected#,found#)@mismatch in has_infoframe .* found
WARNING:at_drivers/gpu/drm/i915/intel_display.c:#check_crtc_state[i915]()@WARNING:.* at .* check_crtc_state+0x
 BYT  igt@gem_pipe_control_store_loop@fresh-buffer      FAIL(1)TIMEOUT(4)PASS(3)      TIMEOUT(2)
*BYT  igt@gem_tiled_pread      FAIL(1)PASS(2)      DMESG_WARN(1)PASS(1)
(dmesg patch applied)drm:check_crtc_state[i915]]*ERROR*mismatch_in_has_infoframe(expected#,found#)@mismatch in has_infoframe .* found
WARNING:at_drivers/gpu/drm/i915/intel_display.c:#check_crtc_state[i915]()@WARNING:.* at .* check_crtc_state+0x
*BDW  igt@gem_userptr_blits@forked-sync-swapping-multifd-mempressure-normal      PASS(2)      NO_RESULT(1)PASS(1)
Note: You need to pay more attention to line start with '*'
deepak.s@linux.intel.com April 30, 2015, 10:12 a.m. UTC | #4
On Thursday 30 April 2015 01:23 AM, Ville Syrjälä wrote:
> On Wed, Apr 29, 2015 at 06:31:56PM +0300, Ville Syrjälä wrote:
>> On Wed, Apr 29, 2015 at 08:23:21AM +0530, deepak.s@linux.intel.com wrote:
>>> From: Deepak S <deepak.s@linux.intel.com>
>>>
>>> After feedback from the hardware team, now we set the GPU min/idel freq to RPe.
>>> Punit is expecting us to operate GPU between Rpe & Rp0. If we drop the
>>> frequency to RPn, punit is failing to change the input voltage to
>>> minimum :(
>> So far I can't reproduce this problem on my BSW. In fact what I see
>> that the voltage at RPn is lower than the voltage at RPe, even while
>> we're in rc6.
>>
>> without forcewake:
>> RPn -> 0x66
>> RPe -> 0x67
>> RP0 -> 0x69
>>
>> with forcewake:
>> RPn -> 0x66
>> RPe -> 0x76
>> RP0 -> 0x9d
>>
>> Also asking Punit to change the frequency after the GPU has gone to
>> rc6 does absolutely nothing (remind anyone of VLV?). I think I need to
>> retest my VLV C0 to see if my earlier observations there were accurate.
>> The shared Vnn rail does make it harder to observe this stuff on
>> VLV though.
> I went back to my VLVs (had a B3 and C0 actually). And I'm seeing the
> exact same behaviour on both, ie. requesting a new frequency from Punit
> does nothing when the GPU is in rc6, and if I let it enter rc6 with a
> high frequency Vnn also remains high. Previously I had thought that C0
> fixed this, but now it definitely shows the same problem here. I must
> have had some accidental forcewake somewhere when I originally tested
> it,
>
> So based on that, your other patch to remove the stepping check from
> vlv_set_rps_idle() is in fact correct.
>
> The question remains however what should we do with CHV. According to my
> testing to get the minimum voltage we should keep RPn around, and we
> should also do the vlv_set_rps_idle() workaround on CHV.
>
> Oh and I also observed something else on VLV. Normally when entering rc6
> the GPLL ref clock gets trunk gated at CCK (by Punit I assume). However
> when using the vlv_gfx_clock_force() that doesn't happen. So I'm not
> entirely sure the GPLL gets turned off properly in that case. Maybe we
> should just use forcewake instead? Oh and BTW, CHV doesn't do the trunk
> gating in either case. I'm not sure where to check if the GPLL is
> actually running or not.
>
Hi Ville,

Thanks Ville for verifying on VLV and CHV. Its interesting to see when Idle,
Voltage not dropping to Vnn on CHV :( This was supposed to be fixed
in BSW/CHV :(. As you suggested it would be better to extend the VLV WA to
CHV also to make sure we drop the voltage when idle.

Below is the sequence I think we should follow (based  on your comments).
1. forcewake power wells
2. do gfx force clock on
3. request freq to punit
4. release gfx force clock on
5. release forcewake of power wells.

Please share your thoughts?

Thanks
Deepak

>> So based on my tests this patch feels a bit wrong.
>>
>>> Since Punit validates the rps range [RPe, RP0]. This patch
>>> removes unused cherryview_rps_min_freq function.
>>>
>>> v2: Change commit message
>>>
>>> v3: set min_freq before idle_freq (chris)
>>>
>>> v4: Squash 'Remove unused rps min function' patch
>>>
>>> Signed-off-by: Deepak S <deepak.s@linux.intel.com>
>>> Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
>>> ---
>>>   drivers/gpu/drm/i915/intel_pm.c | 21 ++-------------------
>>>   1 file changed, 2 insertions(+), 19 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
>>> index a7516ed..78c89ff 100644
>>> --- a/drivers/gpu/drm/i915/intel_pm.c
>>> +++ b/drivers/gpu/drm/i915/intel_pm.c
>>> @@ -4715,24 +4715,6 @@ static int cherryview_rps_guar_freq(struct drm_i915_private *dev_priv)
>>>   	return rp1;
>>>   }
>>>   
>>> -static int cherryview_rps_min_freq(struct drm_i915_private *dev_priv)
>>> -{
>>> -	struct drm_device *dev = dev_priv->dev;
>>> -	u32 val, rpn;
>>> -
>>> -	if (dev->pdev->revision >= 0x20) {
>>> -		val = vlv_punit_read(dev_priv, FB_GFX_FMIN_AT_VMIN_FUSE);
>>> -		rpn = ((val >> FB_GFX_FMIN_AT_VMIN_FUSE_SHIFT) &
>>> -		       FB_GFX_FREQ_FUSE_MASK);
>>> -	} else { /* For pre-production hardware */
>>> -		val = vlv_punit_read(dev_priv, PUNIT_GPU_STATUS_REG);
>>> -		rpn = ((val >> PUNIT_GPU_STATIS_GFX_MIN_FREQ_SHIFT) &
>>> -		       PUNIT_GPU_STATUS_GFX_MIN_FREQ_MASK);
>>> -	}
>>> -
>>> -	return rpn;
>>> -}
>>> -
>>>   static int valleyview_rps_guar_freq(struct drm_i915_private *dev_priv)
>>>   {
>>>   	u32 val, rp1;
>>> @@ -4984,7 +4966,8 @@ static void cherryview_init_gt_powersave(struct drm_device *dev)
>>>   			 intel_gpu_freq(dev_priv, dev_priv->rps.rp1_freq),
>>>   			 dev_priv->rps.rp1_freq);
>>>   
>>> -	dev_priv->rps.min_freq = cherryview_rps_min_freq(dev_priv);
>>> +	/* PUnit validated range is only [RPe, RP0] */
>>> +	dev_priv->rps.min_freq = dev_priv->rps.efficient_freq;
>>>   	DRM_DEBUG_DRIVER("min GPU freq: %d MHz (%u)\n",
>>>   			 intel_gpu_freq(dev_priv, dev_priv->rps.min_freq),
>>>   			 dev_priv->rps.min_freq);
>>> -- 
>>> 1.9.1
>> -- 
>> Ville Syrjälä
>> Intel OTC
>> _______________________________________________
>> Intel-gfx mailing list
>> Intel-gfx@lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
Ville Syrjälä April 30, 2015, 11:19 a.m. UTC | #5
On Thu, Apr 30, 2015 at 03:42:42PM +0530, Deepak S wrote:
> 
> 
> On Thursday 30 April 2015 01:23 AM, Ville Syrjälä wrote:
> > On Wed, Apr 29, 2015 at 06:31:56PM +0300, Ville Syrjälä wrote:
> >> On Wed, Apr 29, 2015 at 08:23:21AM +0530, deepak.s@linux.intel.com wrote:
> >>> From: Deepak S <deepak.s@linux.intel.com>
> >>>
> >>> After feedback from the hardware team, now we set the GPU min/idel freq to RPe.
> >>> Punit is expecting us to operate GPU between Rpe & Rp0. If we drop the
> >>> frequency to RPn, punit is failing to change the input voltage to
> >>> minimum :(
> >> So far I can't reproduce this problem on my BSW. In fact what I see
> >> that the voltage at RPn is lower than the voltage at RPe, even while
> >> we're in rc6.
> >>
> >> without forcewake:
> >> RPn -> 0x66
> >> RPe -> 0x67
> >> RP0 -> 0x69
> >>
> >> with forcewake:
> >> RPn -> 0x66
> >> RPe -> 0x76
> >> RP0 -> 0x9d
> >>
> >> Also asking Punit to change the frequency after the GPU has gone to
> >> rc6 does absolutely nothing (remind anyone of VLV?). I think I need to
> >> retest my VLV C0 to see if my earlier observations there were accurate.
> >> The shared Vnn rail does make it harder to observe this stuff on
> >> VLV though.
> > I went back to my VLVs (had a B3 and C0 actually). And I'm seeing the
> > exact same behaviour on both, ie. requesting a new frequency from Punit
> > does nothing when the GPU is in rc6, and if I let it enter rc6 with a
> > high frequency Vnn also remains high. Previously I had thought that C0
> > fixed this, but now it definitely shows the same problem here. I must
> > have had some accidental forcewake somewhere when I originally tested
> > it,
> >
> > So based on that, your other patch to remove the stepping check from
> > vlv_set_rps_idle() is in fact correct.
> >
> > The question remains however what should we do with CHV. According to my
> > testing to get the minimum voltage we should keep RPn around, and we
> > should also do the vlv_set_rps_idle() workaround on CHV.
> >
> > Oh and I also observed something else on VLV. Normally when entering rc6
> > the GPLL ref clock gets trunk gated at CCK (by Punit I assume). However
> > when using the vlv_gfx_clock_force() that doesn't happen. So I'm not
> > entirely sure the GPLL gets turned off properly in that case. Maybe we
> > should just use forcewake instead? Oh and BTW, CHV doesn't do the trunk
> > gating in either case. I'm not sure where to check if the GPLL is
> > actually running or not.
> >
> Hi Ville,
> 
> Thanks Ville for verifying on VLV and CHV. Its interesting to see when Idle,
> Voltage not dropping to Vnn on CHV :( This was supposed to be fixed
> in BSW/CHV :(.

Well it does drop, but not quite all the way if the current
frequency is above RPn.

I just tried to look at the energy numbers from RAPL a bit. Based
on that the difference in Vgg when forcewake is off is rather
insignificant, or the Vgg portion of the always-on well is so small
that it doesn't really matter.

With forcewake enabled I see a clear difference between RPn and
RPe though. But that might mostly matter for cases where would grab
forcewake without actually feeding any work to the GPU. That might
be rare enough to not make much of a difference in practice.

> As you suggested it would be better to extend the VLV WA to
> CHV also to make sure we drop the voltage when idle.
> 
> Below is the sequence I think we should follow (based  on your comments).
> 1. forcewake power wells
> 2. do gfx force clock on
> 3. request freq to punit
> 4. release gfx force clock on
> 5. release forcewake of power wells.
> 
> Please share your thoughts?

I'm thinking we shouldn't need the gfx clock force since forcewake
should already cause the clock to be enabled.

I've also not verified what happens if we drop the forcewake before
Punit has actually finished the frequency change. I'll try to hack
up some kind of test to see if I can make that happen.

> 
> Thanks
> Deepak
> 
> >> So based on my tests this patch feels a bit wrong.
> >>
> >>> Since Punit validates the rps range [RPe, RP0]. This patch
> >>> removes unused cherryview_rps_min_freq function.
> >>>
> >>> v2: Change commit message
> >>>
> >>> v3: set min_freq before idle_freq (chris)
> >>>
> >>> v4: Squash 'Remove unused rps min function' patch
> >>>
> >>> Signed-off-by: Deepak S <deepak.s@linux.intel.com>
> >>> Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
> >>> ---
> >>>   drivers/gpu/drm/i915/intel_pm.c | 21 ++-------------------
> >>>   1 file changed, 2 insertions(+), 19 deletions(-)
> >>>
> >>> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> >>> index a7516ed..78c89ff 100644
> >>> --- a/drivers/gpu/drm/i915/intel_pm.c
> >>> +++ b/drivers/gpu/drm/i915/intel_pm.c
> >>> @@ -4715,24 +4715,6 @@ static int cherryview_rps_guar_freq(struct drm_i915_private *dev_priv)
> >>>   	return rp1;
> >>>   }
> >>>   
> >>> -static int cherryview_rps_min_freq(struct drm_i915_private *dev_priv)
> >>> -{
> >>> -	struct drm_device *dev = dev_priv->dev;
> >>> -	u32 val, rpn;
> >>> -
> >>> -	if (dev->pdev->revision >= 0x20) {
> >>> -		val = vlv_punit_read(dev_priv, FB_GFX_FMIN_AT_VMIN_FUSE);
> >>> -		rpn = ((val >> FB_GFX_FMIN_AT_VMIN_FUSE_SHIFT) &
> >>> -		       FB_GFX_FREQ_FUSE_MASK);
> >>> -	} else { /* For pre-production hardware */
> >>> -		val = vlv_punit_read(dev_priv, PUNIT_GPU_STATUS_REG);
> >>> -		rpn = ((val >> PUNIT_GPU_STATIS_GFX_MIN_FREQ_SHIFT) &
> >>> -		       PUNIT_GPU_STATUS_GFX_MIN_FREQ_MASK);
> >>> -	}
> >>> -
> >>> -	return rpn;
> >>> -}
> >>> -
> >>>   static int valleyview_rps_guar_freq(struct drm_i915_private *dev_priv)
> >>>   {
> >>>   	u32 val, rp1;
> >>> @@ -4984,7 +4966,8 @@ static void cherryview_init_gt_powersave(struct drm_device *dev)
> >>>   			 intel_gpu_freq(dev_priv, dev_priv->rps.rp1_freq),
> >>>   			 dev_priv->rps.rp1_freq);
> >>>   
> >>> -	dev_priv->rps.min_freq = cherryview_rps_min_freq(dev_priv);
> >>> +	/* PUnit validated range is only [RPe, RP0] */
> >>> +	dev_priv->rps.min_freq = dev_priv->rps.efficient_freq;
> >>>   	DRM_DEBUG_DRIVER("min GPU freq: %d MHz (%u)\n",
> >>>   			 intel_gpu_freq(dev_priv, dev_priv->rps.min_freq),
> >>>   			 dev_priv->rps.min_freq);
> >>> -- 
> >>> 1.9.1
> >> -- 
> >> Ville Syrjälä
> >> Intel OTC
> >> _______________________________________________
> >> Intel-gfx mailing list
> >> Intel-gfx@lists.freedesktop.org
> >> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
Ville Syrjälä April 30, 2015, 2:05 p.m. UTC | #6
On Thu, Apr 30, 2015 at 02:19:07PM +0300, Ville Syrjälä wrote:
> On Thu, Apr 30, 2015 at 03:42:42PM +0530, Deepak S wrote:
> > As you suggested it would be better to extend the VLV WA to
> > CHV also to make sure we drop the voltage when idle.
> > 
> > Below is the sequence I think we should follow (based  on your comments).
> > 1. forcewake power wells
> > 2. do gfx force clock on
> > 3. request freq to punit
> > 4. release gfx force clock on
> > 5. release forcewake of power wells.
> > 
> > Please share your thoughts?
> 
> I'm thinking we shouldn't need the gfx clock force since forcewake
> should already cause the clock to be enabled.
> 
> I've also not verified what happens if we drop the forcewake before
> Punit has actually finished the frequency change. I'll try to hack
> up some kind of test to see if I can make that happen.

OK, after some hacking I see that the forcewake is enough, and also
we don't seem to need to wait for the Punit to finish the frequency
change before dropping forcewake. It seems to finish the change even
after forcewake has been dropped.

Also for a bit of extra micro optimization we should perhaps wake up
the media well only, as that takes a lot less power than the render
well.

> 
> > 
> > Thanks
> > Deepak
> > 
> > >> So based on my tests this patch feels a bit wrong.
> > >>
> > >>> Since Punit validates the rps range [RPe, RP0]. This patch
> > >>> removes unused cherryview_rps_min_freq function.
> > >>>
> > >>> v2: Change commit message
> > >>>
> > >>> v3: set min_freq before idle_freq (chris)
> > >>>
> > >>> v4: Squash 'Remove unused rps min function' patch
> > >>>
> > >>> Signed-off-by: Deepak S <deepak.s@linux.intel.com>
> > >>> Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
> > >>> ---
> > >>>   drivers/gpu/drm/i915/intel_pm.c | 21 ++-------------------
> > >>>   1 file changed, 2 insertions(+), 19 deletions(-)
> > >>>
> > >>> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > >>> index a7516ed..78c89ff 100644
> > >>> --- a/drivers/gpu/drm/i915/intel_pm.c
> > >>> +++ b/drivers/gpu/drm/i915/intel_pm.c
> > >>> @@ -4715,24 +4715,6 @@ static int cherryview_rps_guar_freq(struct drm_i915_private *dev_priv)
> > >>>   	return rp1;
> > >>>   }
> > >>>   
> > >>> -static int cherryview_rps_min_freq(struct drm_i915_private *dev_priv)
> > >>> -{
> > >>> -	struct drm_device *dev = dev_priv->dev;
> > >>> -	u32 val, rpn;
> > >>> -
> > >>> -	if (dev->pdev->revision >= 0x20) {
> > >>> -		val = vlv_punit_read(dev_priv, FB_GFX_FMIN_AT_VMIN_FUSE);
> > >>> -		rpn = ((val >> FB_GFX_FMIN_AT_VMIN_FUSE_SHIFT) &
> > >>> -		       FB_GFX_FREQ_FUSE_MASK);
> > >>> -	} else { /* For pre-production hardware */
> > >>> -		val = vlv_punit_read(dev_priv, PUNIT_GPU_STATUS_REG);
> > >>> -		rpn = ((val >> PUNIT_GPU_STATIS_GFX_MIN_FREQ_SHIFT) &
> > >>> -		       PUNIT_GPU_STATUS_GFX_MIN_FREQ_MASK);
> > >>> -	}
> > >>> -
> > >>> -	return rpn;
> > >>> -}
> > >>> -
> > >>>   static int valleyview_rps_guar_freq(struct drm_i915_private *dev_priv)
> > >>>   {
> > >>>   	u32 val, rp1;
> > >>> @@ -4984,7 +4966,8 @@ static void cherryview_init_gt_powersave(struct drm_device *dev)
> > >>>   			 intel_gpu_freq(dev_priv, dev_priv->rps.rp1_freq),
> > >>>   			 dev_priv->rps.rp1_freq);
> > >>>   
> > >>> -	dev_priv->rps.min_freq = cherryview_rps_min_freq(dev_priv);
> > >>> +	/* PUnit validated range is only [RPe, RP0] */
> > >>> +	dev_priv->rps.min_freq = dev_priv->rps.efficient_freq;
> > >>>   	DRM_DEBUG_DRIVER("min GPU freq: %d MHz (%u)\n",
> > >>>   			 intel_gpu_freq(dev_priv, dev_priv->rps.min_freq),
> > >>>   			 dev_priv->rps.min_freq);
> > >>> -- 
> > >>> 1.9.1
> > >> -- 
> > >> Ville Syrjälä
> > >> Intel OTC
> > >> _______________________________________________
> > >> Intel-gfx mailing list
> > >> Intel-gfx@lists.freedesktop.org
> > >> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Ville Syrjälä
> Intel OTC
deepak.s@linux.intel.com May 2, 2015, 7:26 a.m. UTC | #7
On Thursday 30 April 2015 07:35 PM, Ville Syrjälä wrote:
> On Thu, Apr 30, 2015 at 02:19:07PM +0300, Ville Syrjälä wrote:
>> On Thu, Apr 30, 2015 at 03:42:42PM +0530, Deepak S wrote:
>>> As you suggested it would be better to extend the VLV WA to
>>> CHV also to make sure we drop the voltage when idle.
>>>
>>> Below is the sequence I think we should follow (based  on your comments).
>>> 1. forcewake power wells
>>> 2. do gfx force clock on
>>> 3. request freq to punit
>>> 4. release gfx force clock on
>>> 5. release forcewake of power wells.
>>>
>>> Please share your thoughts?
>> I'm thinking we shouldn't need the gfx clock force since forcewake
>> should already cause the clock to be enabled.
>>
>> I've also not verified what happens if we drop the forcewake before
>> Punit has actually finished the frequency change. I'll try to hack
>> up some kind of test to see if I can make that happen.
> OK, after some hacking I see that the forcewake is enough, and also
> we don't seem to need to wait for the Punit to finish the frequency
> change before dropping forcewake. It seems to finish the change even
> after forcewake has been dropped.
>
> Also for a bit of extra micro optimization we should perhaps wake up
> the media well only, as that takes a lot less power than the render
> well.

Thanks Ville. I will submit new patch to extend the WA to CHV

Thanks
Deepak

>>> Thanks
>>> Deepak
>>>
>>>>> So based on my tests this patch feels a bit wrong.
>>>>>
>>>>>> Since Punit validates the rps range [RPe, RP0]. This patch
>>>>>> removes unused cherryview_rps_min_freq function.
>>>>>>
>>>>>> v2: Change commit message
>>>>>>
>>>>>> v3: set min_freq before idle_freq (chris)
>>>>>>
>>>>>> v4: Squash 'Remove unused rps min function' patch
>>>>>>
>>>>>> Signed-off-by: Deepak S <deepak.s@linux.intel.com>
>>>>>> Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
>>>>>> ---
>>>>>>    drivers/gpu/drm/i915/intel_pm.c | 21 ++-------------------
>>>>>>    1 file changed, 2 insertions(+), 19 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
>>>>>> index a7516ed..78c89ff 100644
>>>>>> --- a/drivers/gpu/drm/i915/intel_pm.c
>>>>>> +++ b/drivers/gpu/drm/i915/intel_pm.c
>>>>>> @@ -4715,24 +4715,6 @@ static int cherryview_rps_guar_freq(struct drm_i915_private *dev_priv)
>>>>>>    	return rp1;
>>>>>>    }
>>>>>>    
>>>>>> -static int cherryview_rps_min_freq(struct drm_i915_private *dev_priv)
>>>>>> -{
>>>>>> -	struct drm_device *dev = dev_priv->dev;
>>>>>> -	u32 val, rpn;
>>>>>> -
>>>>>> -	if (dev->pdev->revision >= 0x20) {
>>>>>> -		val = vlv_punit_read(dev_priv, FB_GFX_FMIN_AT_VMIN_FUSE);
>>>>>> -		rpn = ((val >> FB_GFX_FMIN_AT_VMIN_FUSE_SHIFT) &
>>>>>> -		       FB_GFX_FREQ_FUSE_MASK);
>>>>>> -	} else { /* For pre-production hardware */
>>>>>> -		val = vlv_punit_read(dev_priv, PUNIT_GPU_STATUS_REG);
>>>>>> -		rpn = ((val >> PUNIT_GPU_STATIS_GFX_MIN_FREQ_SHIFT) &
>>>>>> -		       PUNIT_GPU_STATUS_GFX_MIN_FREQ_MASK);
>>>>>> -	}
>>>>>> -
>>>>>> -	return rpn;
>>>>>> -}
>>>>>> -
>>>>>>    static int valleyview_rps_guar_freq(struct drm_i915_private *dev_priv)
>>>>>>    {
>>>>>>    	u32 val, rp1;
>>>>>> @@ -4984,7 +4966,8 @@ static void cherryview_init_gt_powersave(struct drm_device *dev)
>>>>>>    			 intel_gpu_freq(dev_priv, dev_priv->rps.rp1_freq),
>>>>>>    			 dev_priv->rps.rp1_freq);
>>>>>>    
>>>>>> -	dev_priv->rps.min_freq = cherryview_rps_min_freq(dev_priv);
>>>>>> +	/* PUnit validated range is only [RPe, RP0] */
>>>>>> +	dev_priv->rps.min_freq = dev_priv->rps.efficient_freq;
>>>>>>    	DRM_DEBUG_DRIVER("min GPU freq: %d MHz (%u)\n",
>>>>>>    			 intel_gpu_freq(dev_priv, dev_priv->rps.min_freq),
>>>>>>    			 dev_priv->rps.min_freq);
>>>>>> -- 
>>>>>> 1.9.1
>>>>> -- 
>>>>> Ville Syrjälä
>>>>> Intel OTC
>>>>> _______________________________________________
>>>>> Intel-gfx mailing list
>>>>> Intel-gfx@lists.freedesktop.org
>>>>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>> -- 
>> Ville Syrjälä
>> Intel OTC
Daniel Vetter May 4, 2015, 8:04 a.m. UTC | #8
On Wed, Apr 29, 2015 at 08:23:21AM +0530, deepak.s@linux.intel.com wrote:
> From: Deepak S <deepak.s@linux.intel.com>
> 
> After feedback from the hardware team, now we set the GPU min/idel freq to RPe.
> Punit is expecting us to operate GPU between Rpe & Rp0. If we drop the
> frequency to RPn, punit is failing to change the input voltage to
> minimum :(
> 
> Since Punit validates the rps range [RPe, RP0]. This patch
> removes unused cherryview_rps_min_freq function.
> 
> v2: Change commit message
> 
> v3: set min_freq before idle_freq (chris)
> 
> v4: Squash 'Remove unused rps min function' patch
> 
> Signed-off-by: Deepak S <deepak.s@linux.intel.com>
> Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 21 ++-------------------
>  1 file changed, 2 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index a7516ed..78c89ff 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -4715,24 +4715,6 @@ static int cherryview_rps_guar_freq(struct drm_i915_private *dev_priv)
>  	return rp1;
>  }
>  
> -static int cherryview_rps_min_freq(struct drm_i915_private *dev_priv)
> -{
> -	struct drm_device *dev = dev_priv->dev;
> -	u32 val, rpn;
> -
> -	if (dev->pdev->revision >= 0x20) {
> -		val = vlv_punit_read(dev_priv, FB_GFX_FMIN_AT_VMIN_FUSE);
> -		rpn = ((val >> FB_GFX_FMIN_AT_VMIN_FUSE_SHIFT) &
> -		       FB_GFX_FREQ_FUSE_MASK);
> -	} else { /* For pre-production hardware */
> -		val = vlv_punit_read(dev_priv, PUNIT_GPU_STATUS_REG);
> -		rpn = ((val >> PUNIT_GPU_STATIS_GFX_MIN_FREQ_SHIFT) &
> -		       PUNIT_GPU_STATUS_GFX_MIN_FREQ_MASK);
> -	}
> -
> -	return rpn;
> -}
> -
>  static int valleyview_rps_guar_freq(struct drm_i915_private *dev_priv)
>  {
>  	u32 val, rp1;
> @@ -4984,7 +4966,8 @@ static void cherryview_init_gt_powersave(struct drm_device *dev)
>  			 intel_gpu_freq(dev_priv, dev_priv->rps.rp1_freq),
>  			 dev_priv->rps.rp1_freq);
>  
> -	dev_priv->rps.min_freq = cherryview_rps_min_freq(dev_priv);
> +	/* PUnit validated range is only [RPe, RP0] */
> +	dev_priv->rps.min_freq = dev_priv->rps.efficient_freq;

Shouldn't we instead just adjust the softlimit instead of the hardlimit?
At least it sounds like this isn't all that clear-cut and maybe we want to
allow userspace to still go below. Similar to how with gpu overclocking we
allow headroom but set the softlimit only to the safe range.
-Daniel

>  	DRM_DEBUG_DRIVER("min GPU freq: %d MHz (%u)\n",
>  			 intel_gpu_freq(dev_priv, dev_priv->rps.min_freq),
>  			 dev_priv->rps.min_freq);
> -- 
> 1.9.1
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
diff mbox

Patch

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index a7516ed..78c89ff 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4715,24 +4715,6 @@  static int cherryview_rps_guar_freq(struct drm_i915_private *dev_priv)
 	return rp1;
 }
 
-static int cherryview_rps_min_freq(struct drm_i915_private *dev_priv)
-{
-	struct drm_device *dev = dev_priv->dev;
-	u32 val, rpn;
-
-	if (dev->pdev->revision >= 0x20) {
-		val = vlv_punit_read(dev_priv, FB_GFX_FMIN_AT_VMIN_FUSE);
-		rpn = ((val >> FB_GFX_FMIN_AT_VMIN_FUSE_SHIFT) &
-		       FB_GFX_FREQ_FUSE_MASK);
-	} else { /* For pre-production hardware */
-		val = vlv_punit_read(dev_priv, PUNIT_GPU_STATUS_REG);
-		rpn = ((val >> PUNIT_GPU_STATIS_GFX_MIN_FREQ_SHIFT) &
-		       PUNIT_GPU_STATUS_GFX_MIN_FREQ_MASK);
-	}
-
-	return rpn;
-}
-
 static int valleyview_rps_guar_freq(struct drm_i915_private *dev_priv)
 {
 	u32 val, rp1;
@@ -4984,7 +4966,8 @@  static void cherryview_init_gt_powersave(struct drm_device *dev)
 			 intel_gpu_freq(dev_priv, dev_priv->rps.rp1_freq),
 			 dev_priv->rps.rp1_freq);
 
-	dev_priv->rps.min_freq = cherryview_rps_min_freq(dev_priv);
+	/* PUnit validated range is only [RPe, RP0] */
+	dev_priv->rps.min_freq = dev_priv->rps.efficient_freq;
 	DRM_DEBUG_DRIVER("min GPU freq: %d MHz (%u)\n",
 			 intel_gpu_freq(dev_priv, dev_priv->rps.min_freq),
 			 dev_priv->rps.min_freq);