[Intel-gfx] [PATCH] drm/i915/dp: Poll for DDI Idle status to be 0 after enabling DDI Buf

[Intel-gfx] [PATCH] drm/i915/dp: Poll for DDI Idle status to be 0 after enabling DDI Buf

[Manasi Navare]

The Bspec sequence expects us to poll for DDI Idle status
to be 0 (not idle) with a timeout of 600usecs after enabling the
DDI BUF CTL. But currently in the driver we just wait for 600usecs
without polling so add that.

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Imre Deak <imre.deak@intel.com>
Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
---
 drivers/gpu/drm/i915/display/intel_ddi.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index ca7bb2294d2b..de7e15de0bc5 100644
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -4023,7 +4023,11 @@ static void intel_ddi_prepare_link_retrain(struct intel_dp *intel_dp)
 	intel_de_write(dev_priv, DDI_BUF_CTL(port), intel_dp->DP);
 	intel_de_posting_read(dev_priv, DDI_BUF_CTL(port));
 
-	udelay(600);
+	if (wait_for_us(!(intel_de_read(dev_priv, DDI_BUF_CTL(port)) &
+			  DDI_BUF_IS_IDLE),
+			600))
+		drm_err(&dev_priv->drm, "DDI port:%c buffer idle\n",
+			port_name(port));
 }
 
 static void intel_ddi_set_link_train(struct intel_dp *intel_dp,
-- 
2.19.1

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Re: [Intel-gfx] [PATCH] drm/i915/dp: Poll for DDI Idle status to be 0 after enabling DDI Buf

[Ville Syrjälä]

On Tue, Jun 16, 2020 at 12:30:56PM -0700, Manasi Navare wrote:
> The Bspec sequence expects us to poll for DDI Idle status
> to be 0 (not idle) with a timeout of 600usecs after enabling the
> DDI BUF CTL.

It only says that for newer platforms. We need to either keep
the fixed delay before starting to poll, or someone needs confirm 
how the idle bit really behaves on the older platforms.

> But currently in the driver we just wait for 600usecs
> without polling so add that.
> 
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Imre Deak <imre.deak@intel.com>
> Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index ca7bb2294d2b..de7e15de0bc5 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -4023,7 +4023,11 @@ static void intel_ddi_prepare_link_retrain(struct intel_dp *intel_dp)
>  	intel_de_write(dev_priv, DDI_BUF_CTL(port), intel_dp->DP);
>  	intel_de_posting_read(dev_priv, DDI_BUF_CTL(port));
>  
> -	udelay(600);
> +	if (wait_for_us(!(intel_de_read(dev_priv, DDI_BUF_CTL(port)) &
> +			  DDI_BUF_IS_IDLE),
> +			600))
> +		drm_err(&dev_priv->drm, "DDI port:%c buffer idle\n",
> +			port_name(port));
>  }
>  
>  static void intel_ddi_set_link_train(struct intel_dp *intel_dp,
> -- 
> 2.19.1

-- 
Ville Syrjälä
Intel
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Re: [Intel-gfx] [PATCH] drm/i915/dp: Poll for DDI Idle status to be 0 after enabling DDI Buf

[Ville Syrjälä]

On Tue, Jun 16, 2020 at 10:42:44PM +0300, Ville Syrjälä wrote:
> On Tue, Jun 16, 2020 at 12:30:56PM -0700, Manasi Navare wrote:
> > The Bspec sequence expects us to poll for DDI Idle status
> > to be 0 (not idle) with a timeout of 600usecs after enabling the
> > DDI BUF CTL.
> 
> It only says that for newer platforms. We need to either keep
> the fixed delay before starting to poll, or someone needs confirm 
> how the idle bit really behaves on the older platforms.

In fact it says not to use this bit at all on BXT. So even our disable
sequence is potentially borked on BXT. Unfortunately the spec doesn't
say which way the bit is broken, so not clear if that's the case or
not.

> 
> > But currently in the driver we just wait for 600usecs
> > without polling so add that.
> > 
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Cc: Imre Deak <imre.deak@intel.com>
> > Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_ddi.c | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> > index ca7bb2294d2b..de7e15de0bc5 100644
> > --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> > @@ -4023,7 +4023,11 @@ static void intel_ddi_prepare_link_retrain(struct intel_dp *intel_dp)
> >  	intel_de_write(dev_priv, DDI_BUF_CTL(port), intel_dp->DP);
> >  	intel_de_posting_read(dev_priv, DDI_BUF_CTL(port));
> >  
> > -	udelay(600);
> > +	if (wait_for_us(!(intel_de_read(dev_priv, DDI_BUF_CTL(port)) &
> > +			  DDI_BUF_IS_IDLE),
> > +			600))
> > +		drm_err(&dev_priv->drm, "DDI port:%c buffer idle\n",
> > +			port_name(port));
> >  }
> >  
> >  static void intel_ddi_set_link_train(struct intel_dp *intel_dp,
> > -- 
> > 2.19.1
> 
> -- 
> Ville Syrjälä
> Intel
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Ville Syrjälä
Intel
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Re: [Intel-gfx] [PATCH] drm/i915/dp: Poll for DDI Idle status to be 0 after enabling DDI Buf

[Manasi Navare]

On Tue, Jun 16, 2020 at 10:54:22PM +0300, Ville Syrjälä wrote:
> On Tue, Jun 16, 2020 at 10:42:44PM +0300, Ville Syrjälä wrote:
> > On Tue, Jun 16, 2020 at 12:30:56PM -0700, Manasi Navare wrote:
> > > The Bspec sequence expects us to poll for DDI Idle status
> > > to be 0 (not idle) with a timeout of 600usecs after enabling the
> > > DDI BUF CTL.
> > 
> > It only says that for newer platforms. We need to either keep
> > the fixed delay before starting to poll, or someone needs confirm 
> > how the idle bit really behaves on the older platforms.
> 
> In fact it says not to use this bit at all on BXT. So even our disable
> sequence is potentially borked on BXT. Unfortunately the spec doesn't
> say which way the bit is broken, so not clear if that's the case or
> not.
>

I double checked on Gen 9, it is > 518 usecs timeout and Gen 10+
it is 500usecs and then gen 12, it is 600 usecs timeout.

Should we add this max timeout for Gen >=10, we def need this for
platforms starting Gen 10+

Manasi
 
> > 
> > > But currently in the driver we just wait for 600usecs
> > > without polling so add that.
> > > 
> > > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > Cc: Imre Deak <imre.deak@intel.com>
> > > Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/display/intel_ddi.c | 6 +++++-
> > >  1 file changed, 5 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> > > index ca7bb2294d2b..de7e15de0bc5 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> > > @@ -4023,7 +4023,11 @@ static void intel_ddi_prepare_link_retrain(struct intel_dp *intel_dp)
> > >  	intel_de_write(dev_priv, DDI_BUF_CTL(port), intel_dp->DP);
> > >  	intel_de_posting_read(dev_priv, DDI_BUF_CTL(port));
> > >  
> > > -	udelay(600);
> > > +	if (wait_for_us(!(intel_de_read(dev_priv, DDI_BUF_CTL(port)) &
> > > +			  DDI_BUF_IS_IDLE),
> > > +			600))
> > > +		drm_err(&dev_priv->drm, "DDI port:%c buffer idle\n",
> > > +			port_name(port));
> > >  }
> > >  
> > >  static void intel_ddi_set_link_train(struct intel_dp *intel_dp,
> > > -- 
> > > 2.19.1
> > 
> > -- 
> > Ville Syrjälä
> > Intel
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Ville Syrjälä
> Intel
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Re: [Intel-gfx] [PATCH] drm/i915/dp: Poll for DDI Idle status to be 0 after enabling DDI Buf

[Ville Syrjälä]

On Tue, Jun 16, 2020 at 12:30:56PM -0700, Manasi Navare wrote:
> The Bspec sequence expects us to poll for DDI Idle status
> to be 0 (not idle) with a timeout of 600usecs after enabling the
> DDI BUF CTL. But currently in the driver we just wait for 600usecs
> without polling so add that.
> 
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Imre Deak <imre.deak@intel.com>
> Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_ddi.c | 6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> index ca7bb2294d2b..de7e15de0bc5 100644
> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> @@ -4023,7 +4023,11 @@ static void intel_ddi_prepare_link_retrain(struct intel_dp *intel_dp)
>  	intel_de_write(dev_priv, DDI_BUF_CTL(port), intel_dp->DP);
>  	intel_de_posting_read(dev_priv, DDI_BUF_CTL(port));
>  
> -	udelay(600);
> +	if (wait_for_us(!(intel_de_read(dev_priv, DDI_BUF_CTL(port)) &
> +			  DDI_BUF_IS_IDLE),
> +			600))
> +		drm_err(&dev_priv->drm, "DDI port:%c buffer idle\n",
> +			port_name(port));

Another thing I just noticed is that icl+ need this for HDMI as well.
The slightly odd thing is that glk is documented to need this for
DP but not HDMI. But I'm thinking doing it also for glk HDMI should
be fine.

So I guess to line up with the spec we should:
- fixed >518us enable delay for pre-glk (not sure if polling
  would be ok for hsw/bdw/skl)
- poll for enable on glk+
- fixed 16us disable delay for bxt
- poll for disable on !bxt

And do it for both DP and HDMI for consistency.


>  }
>  
>  static void intel_ddi_set_link_train(struct intel_dp *intel_dp,
> -- 
> 2.19.1

-- 
Ville Syrjälä
Intel
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Re: [Intel-gfx] [PATCH] drm/i915/dp: Poll for DDI Idle status to be 0 after enabling DDI Buf

[Manasi Navare]

On Tue, Jun 16, 2020 at 11:22:32PM +0300, Ville Syrjälä wrote:
> On Tue, Jun 16, 2020 at 12:30:56PM -0700, Manasi Navare wrote:
> > The Bspec sequence expects us to poll for DDI Idle status
> > to be 0 (not idle) with a timeout of 600usecs after enabling the
> > DDI BUF CTL. But currently in the driver we just wait for 600usecs
> > without polling so add that.
> > 
> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Cc: Imre Deak <imre.deak@intel.com>
> > Signed-off-by: Manasi Navare <manasi.d.navare@intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_ddi.c | 6 +++++-
> >  1 file changed, 5 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> > index ca7bb2294d2b..de7e15de0bc5 100644
> > --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> > @@ -4023,7 +4023,11 @@ static void intel_ddi_prepare_link_retrain(struct intel_dp *intel_dp)
> >  	intel_de_write(dev_priv, DDI_BUF_CTL(port), intel_dp->DP);
> >  	intel_de_posting_read(dev_priv, DDI_BUF_CTL(port));
> >  
> > -	udelay(600);
> > +	if (wait_for_us(!(intel_de_read(dev_priv, DDI_BUF_CTL(port)) &
> > +			  DDI_BUF_IS_IDLE),
> > +			600))
> > +		drm_err(&dev_priv->drm, "DDI port:%c buffer idle\n",
> > +			port_name(port));
> 
> Another thing I just noticed is that icl+ need this for HDMI as well.
> The slightly odd thing is that glk is documented to need this for
> DP but not HDMI. But I'm thinking doing it also for glk HDMI should
> be fine.
> 
> So I guess to line up with the spec we should:
> - fixed >518us enable delay for pre-glk (not sure if polling
>   would be ok for hsw/bdw/skl)
> - poll for enable on glk+
> - fixed 16us disable delay for bxt
> - poll for disable on !bxt
> 
> And do it for both DP and HDMI for consistency.

So since its different one each platform, should we create a per platform hook
like wait_for_non_idle_status or something per platform?

Manasi

> 
> 
> >  }
> >  
> >  static void intel_ddi_set_link_train(struct intel_dp *intel_dp,
> > -- 
> > 2.19.1
> 
> -- 
> Ville Syrjälä
> Intel
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[Intel-gfx] ✓ Fi.CI.BAT: success for drm/i915/dp: Poll for DDI Idle status to be 0 after enabling DDI Buf

[Patchwork]

== Series Details ==

Series: drm/i915/dp: Poll for DDI Idle status to be 0 after enabling DDI Buf
URL   : https://patchwork.freedesktop.org/series/78435/
State : success

== Summary ==

CI Bug Log - changes from CI_DRM_8636 -> Patchwork_17970
====================================================

Summary
-------

  **SUCCESS**

  No regressions found.

  External URL: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17970/index.html

Known issues
------------

  Here are the changes found in Patchwork_17970 that come from known issues:

### IGT changes ###

#### Issues hit ####

  * igt@i915_pm_rpm@basic-pci-d3-state:
    - fi-bsw-kefka:       [PASS][1] -> [DMESG-WARN][2] ([i915#1982])
   [1]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8636/fi-bsw-kefka/igt@i915_pm_rpm@basic-pci-d3-state.html
   [2]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17970/fi-bsw-kefka/igt@i915_pm_rpm@basic-pci-d3-state.html

  * igt@kms_flip@basic-flip-vs-wf_vblank@c-edp1:
    - fi-icl-u2:          [PASS][3] -> [DMESG-WARN][4] ([i915#1982]) +1 similar issue
   [3]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8636/fi-icl-u2/igt@kms_flip@basic-flip-vs-wf_vblank@c-edp1.html
   [4]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17970/fi-icl-u2/igt@kms_flip@basic-flip-vs-wf_vblank@c-edp1.html

  
#### Possible fixes ####

  * igt@i915_pm_rpm@module-reload:
    - fi-glk-dsi:         [DMESG-WARN][5] ([i915#1982]) -> [PASS][6]
   [5]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8636/fi-glk-dsi/igt@i915_pm_rpm@module-reload.html
   [6]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17970/fi-glk-dsi/igt@i915_pm_rpm@module-reload.html

  * igt@kms_chamelium@hdmi-hpd-fast:
    - fi-kbl-7500u:       [FAIL][7] ([i915#227]) -> [PASS][8]
   [7]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8636/fi-kbl-7500u/igt@kms_chamelium@hdmi-hpd-fast.html
   [8]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17970/fi-kbl-7500u/igt@kms_chamelium@hdmi-hpd-fast.html

  * igt@kms_cursor_legacy@basic-busy-flip-before-cursor-atomic:
    - fi-icl-u2:          [DMESG-WARN][9] ([i915#1982]) -> [PASS][10]
   [9]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8636/fi-icl-u2/igt@kms_cursor_legacy@basic-busy-flip-before-cursor-atomic.html
   [10]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17970/fi-icl-u2/igt@kms_cursor_legacy@basic-busy-flip-before-cursor-atomic.html

  
#### Warnings ####

  * igt@gem_exec_suspend@basic-s0:
    - fi-kbl-x1275:       [DMESG-WARN][11] ([i915#62] / [i915#92] / [i915#95]) -> [DMESG-WARN][12] ([i915#1982] / [i915#62] / [i915#92] / [i915#95])
   [11]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8636/fi-kbl-x1275/igt@gem_exec_suspend@basic-s0.html
   [12]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17970/fi-kbl-x1275/igt@gem_exec_suspend@basic-s0.html

  * igt@gem_exec_suspend@basic-s3:
    - fi-kbl-x1275:       [DMESG-WARN][13] ([i915#62] / [i915#92]) -> [DMESG-WARN][14] ([i915#62] / [i915#92] / [i915#95])
   [13]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8636/fi-kbl-x1275/igt@gem_exec_suspend@basic-s3.html
   [14]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17970/fi-kbl-x1275/igt@gem_exec_suspend@basic-s3.html

  * igt@i915_pm_rpm@basic-rte:
    - fi-kbl-guc:         [FAIL][15] ([i915#665] / [i915#704]) -> [SKIP][16] ([fdo#109271])
   [15]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8636/fi-kbl-guc/igt@i915_pm_rpm@basic-rte.html
   [16]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17970/fi-kbl-guc/igt@i915_pm_rpm@basic-rte.html

  * igt@kms_flip@basic-flip-vs-modeset@a-dp1:
    - fi-kbl-x1275:       [DMESG-WARN][17] ([i915#62] / [i915#92] / [i915#95]) -> [DMESG-WARN][18] ([i915#62] / [i915#92]) +4 similar issues
   [17]: https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_8636/fi-kbl-x1275/igt@kms_flip@basic-flip-vs-modeset@a-dp1.html
   [18]: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17970/fi-kbl-x1275/igt@kms_flip@basic-flip-vs-modeset@a-dp1.html

  
  {name}: This element is suppressed. This means it is ignored when computing
          the status of the difference (SUCCESS, WARNING, or FAILURE).

  [fdo#109271]: https://bugs.freedesktop.org/show_bug.cgi?id=109271
  [i915#1569]: https://gitlab.freedesktop.org/drm/intel/issues/1569
  [i915#192]: https://gitlab.freedesktop.org/drm/intel/issues/192
  [i915#193]: https://gitlab.freedesktop.org/drm/intel/issues/193
  [i915#194]: https://gitlab.freedesktop.org/drm/intel/issues/194
  [i915#1982]: https://gitlab.freedesktop.org/drm/intel/issues/1982
  [i915#2029]: https://gitlab.freedesktop.org/drm/intel/issues/2029
  [i915#227]: https://gitlab.freedesktop.org/drm/intel/issues/227
  [i915#62]: https://gitlab.freedesktop.org/drm/intel/issues/62
  [i915#665]: https://gitlab.freedesktop.org/drm/intel/issues/665
  [i915#704]: https://gitlab.freedesktop.org/drm/intel/issues/704
  [i915#92]: https://gitlab.freedesktop.org/drm/intel/issues/92
  [i915#95]: https://gitlab.freedesktop.org/drm/intel/issues/95


Participating hosts (47 -> 40)
------------------------------

  Missing    (7): fi-ilk-m540 fi-byt-j1900 fi-byt-squawks fi-bsw-cyan fi-cfl-guc fi-byt-clapper fi-bdw-samus 


Build changes
-------------

  * Linux: CI_DRM_8636 -> Patchwork_17970

  CI-20190529: 20190529
  CI_DRM_8636: dd73f1f0cf1ea35520ff8267e59159be8c884e23 @ git://anongit.freedesktop.org/gfx-ci/linux
  IGT_5711: 90611a0c90afa4a46496c78a4faf9638a1538ac3 @ git://anongit.freedesktop.org/xorg/app/intel-gpu-tools
  Patchwork_17970: 56786c7f15db8d8f1ad41d0e56de30044599d33a @ git://anongit.freedesktop.org/gfx-ci/linux


== Linux commits ==

56786c7f15db drm/i915/dp: Poll for DDI Idle status to be 0 after enabling DDI Buf

== Logs ==

For more details see: https://intel-gfx-ci.01.org/tree/drm-tip/Patchwork_17970/index.html
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