diff mbox series

[v1,2/3] drm/i915/dsc: force full modeset whenever DSC is enabled at probe

Message ID 20200213140412.32697-3-stanislav.lisovskiy@intel.com (mailing list archive)
State New, archived
Headers show
Series Fix modeset transitions related to DBuf | expand

Commit Message

Lisovskiy, Stanislav Feb. 13, 2020, 2:04 p.m. UTC 
From: Jani Nikula <jani.nikula@intel.com>

We lack full state readout of DSC config, which may lead to DSC enable
using a config that's all zeros, failing spectacularly. Force full
modeset and thus compute config at probe to get a sane state, until we
implement DSC state readout. Any fastset that did appear to work with
DSC at probe, worked by coincidence. [1] is an example of a change that
triggered the issue on TGL DSI DSC.

[1] http://patchwork.freedesktop.org/patch/msgid/20200212150102.7600-1-ville.syrjala@linux.intel.com

Cc: Manasi Navare <manasi.d.navare@intel.com>
Cc: Vandita Kulkarni <vandita.kulkarni@intel.com>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/i915/display/intel_display.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

Comments

Matt Roper Feb. 13, 2020, 8:56 p.m. UTC | #1 
On Thu, Feb 13, 2020 at 04:04:11PM +0200, Stanislav Lisovskiy wrote:
> From: Jani Nikula <jani.nikula@intel.com>
> 
> We lack full state readout of DSC config, which may lead to DSC enable
> using a config that's all zeros, failing spectacularly. Force full
> modeset and thus compute config at probe to get a sane state, until we
> implement DSC state readout. Any fastset that did appear to work with
> DSC at probe, worked by coincidence. [1] is an example of a change that
> triggered the issue on TGL DSI DSC.
> 
> [1] http://patchwork.freedesktop.org/patch/msgid/20200212150102.7600-1-ville.syrjala@linux.intel.com
> 
> Cc: Manasi Navare <manasi.d.navare@intel.com>
> Cc: Vandita Kulkarni <vandita.kulkarni@intel.com>
> Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
> Cc: stable@vger.kernel.org
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Should this be

Fixes: fbacb15ea814 ("drm/i915/dsc: add basic hardware state readout support")

since that's where we added the basic readout with a FIXME to add more
later?

I don't know the specifics of DSC and what state we need, but the
approach here seems reasonable.

Acked-by: Matt Roper <matthew.d.roper@intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 61ba1f2256a0..1e3f2cc27db8 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -17828,6 +17828,24 @@ static int intel_initial_commit(struct drm_device *dev)
>  			 * have readout for pipe gamma enable.
>  			 */
>  			crtc_state->uapi.color_mgmt_changed = true;
> +
> +			/*
> +			 * FIXME hack to force full modeset when DSC is being
> +			 * used.
> +			 *
> +			 * As long as we do not have full state readout and
> +			 * config comparison of crtc_state->dsc, we have no way
> +			 * to ensure reliable fastset. Remove once we have
> +			 * readout for DSC.
> +			 */
> +			if (crtc_state->dsc.compression_enable) {
> +				ret = drm_atomic_add_affected_connectors(state,
> +									 &crtc->base);
> +				if (ret)
> +					goto out;
> +				crtc_state->uapi.mode_changed = true;
> +				drm_dbg_kms(dev, "Force full modeset for DSC\n");
> +			}
>  		}
>  	}
>  
> -- 
> 2.24.1.485.gad05a3d8e5
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Jani Nikula Feb. 13, 2020, 9:03 p.m. UTC | #2 
On Thu, 13 Feb 2020, Matt Roper <matthew.d.roper@intel.com> wrote:
> On Thu, Feb 13, 2020 at 04:04:11PM +0200, Stanislav Lisovskiy wrote:
>> From: Jani Nikula <jani.nikula@intel.com>
>> 
>> We lack full state readout of DSC config, which may lead to DSC enable
>> using a config that's all zeros, failing spectacularly. Force full
>> modeset and thus compute config at probe to get a sane state, until we
>> implement DSC state readout. Any fastset that did appear to work with
>> DSC at probe, worked by coincidence. [1] is an example of a change that
>> triggered the issue on TGL DSI DSC.
>> 
>> [1] http://patchwork.freedesktop.org/patch/msgid/20200212150102.7600-1-ville.syrjala@linux.intel.com
>> 
>> Cc: Manasi Navare <manasi.d.navare@intel.com>
>> Cc: Vandita Kulkarni <vandita.kulkarni@intel.com>
>> Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
>> Cc: stable@vger.kernel.org
>> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>
> Should this be
>
> Fixes: fbacb15ea814 ("drm/i915/dsc: add basic hardware state readout support")
>
> since that's where we added the basic readout with a FIXME to add more
> later?

That added some readout and checks, but the problem existed before them
too.

BR,
Jani.



>
> I don't know the specifics of DSC and what state we need, but the
> approach here seems reasonable.
>
> Acked-by: Matt Roper <matthew.d.roper@intel.com>
>
>> ---
>>  drivers/gpu/drm/i915/display/intel_display.c | 18 ++++++++++++++++++
>>  1 file changed, 18 insertions(+)
>> 
>> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
>> index 61ba1f2256a0..1e3f2cc27db8 100644
>> --- a/drivers/gpu/drm/i915/display/intel_display.c
>> +++ b/drivers/gpu/drm/i915/display/intel_display.c
>> @@ -17828,6 +17828,24 @@ static int intel_initial_commit(struct drm_device *dev)
>>  			 * have readout for pipe gamma enable.
>>  			 */
>>  			crtc_state->uapi.color_mgmt_changed = true;
>> +
>> +			/*
>> +			 * FIXME hack to force full modeset when DSC is being
>> +			 * used.
>> +			 *
>> +			 * As long as we do not have full state readout and
>> +			 * config comparison of crtc_state->dsc, we have no way
>> +			 * to ensure reliable fastset. Remove once we have
>> +			 * readout for DSC.
>> +			 */
>> +			if (crtc_state->dsc.compression_enable) {
>> +				ret = drm_atomic_add_affected_connectors(state,
>> +									 &crtc->base);
>> +				if (ret)
>> +					goto out;
>> +				crtc_state->uapi.mode_changed = true;
>> +				drm_dbg_kms(dev, "Force full modeset for DSC\n");
>> +			}
>>  		}
>>  	}
>>  
>> -- 
>> 2.24.1.485.gad05a3d8e5
>> 
>> _______________________________________________
>> Intel-gfx mailing list
>> Intel-gfx@lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
Matt Roper Feb. 13, 2020, 9:06 p.m. UTC | #3 
On Thu, Feb 13, 2020 at 11:03:29PM +0200, Jani Nikula wrote:
> On Thu, 13 Feb 2020, Matt Roper <matthew.d.roper@intel.com> wrote:
> > On Thu, Feb 13, 2020 at 04:04:11PM +0200, Stanislav Lisovskiy wrote:
> >> From: Jani Nikula <jani.nikula@intel.com>
> >> 
> >> We lack full state readout of DSC config, which may lead to DSC enable
> >> using a config that's all zeros, failing spectacularly. Force full
> >> modeset and thus compute config at probe to get a sane state, until we
> >> implement DSC state readout. Any fastset that did appear to work with
> >> DSC at probe, worked by coincidence. [1] is an example of a change that
> >> triggered the issue on TGL DSI DSC.
> >> 
> >> [1] http://patchwork.freedesktop.org/patch/msgid/20200212150102.7600-1-ville.syrjala@linux.intel.com
> >> 
> >> Cc: Manasi Navare <manasi.d.navare@intel.com>
> >> Cc: Vandita Kulkarni <vandita.kulkarni@intel.com>
> >> Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
> >> Cc: stable@vger.kernel.org
> >> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> >
> > Should this be
> >
> > Fixes: fbacb15ea814 ("drm/i915/dsc: add basic hardware state readout support")
> >
> > since that's where we added the basic readout with a FIXME to add more
> > later?
> 
> That added some readout and checks, but the problem existed before them
> too.

Right, but that's as far back as we can go with a fix, right?  Since
before that we don't even read out enough to know that compression is
enabled?


Matt

> 
> BR,
> Jani.
> 
> 
> 
> >
> > I don't know the specifics of DSC and what state we need, but the
> > approach here seems reasonable.
> >
> > Acked-by: Matt Roper <matthew.d.roper@intel.com>
> >
> >> ---
> >>  drivers/gpu/drm/i915/display/intel_display.c | 18 ++++++++++++++++++
> >>  1 file changed, 18 insertions(+)
> >> 
> >> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> >> index 61ba1f2256a0..1e3f2cc27db8 100644
> >> --- a/drivers/gpu/drm/i915/display/intel_display.c
> >> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> >> @@ -17828,6 +17828,24 @@ static int intel_initial_commit(struct drm_device *dev)
> >>  			 * have readout for pipe gamma enable.
> >>  			 */
> >>  			crtc_state->uapi.color_mgmt_changed = true;
> >> +
> >> +			/*
> >> +			 * FIXME hack to force full modeset when DSC is being
> >> +			 * used.
> >> +			 *
> >> +			 * As long as we do not have full state readout and
> >> +			 * config comparison of crtc_state->dsc, we have no way
> >> +			 * to ensure reliable fastset. Remove once we have
> >> +			 * readout for DSC.
> >> +			 */
> >> +			if (crtc_state->dsc.compression_enable) {
> >> +				ret = drm_atomic_add_affected_connectors(state,
> >> +									 &crtc->base);
> >> +				if (ret)
> >> +					goto out;
> >> +				crtc_state->uapi.mode_changed = true;
> >> +				drm_dbg_kms(dev, "Force full modeset for DSC\n");
> >> +			}
> >>  		}
> >>  	}
> >>  
> >> -- 
> >> 2.24.1.485.gad05a3d8e5
> >> 
> >> _______________________________________________
> >> Intel-gfx mailing list
> >> Intel-gfx@lists.freedesktop.org
> >> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> -- 
> Jani Nikula, Intel Open Source Graphics Center
Jani Nikula Feb. 13, 2020, 9:21 p.m. UTC | #4 
On Thu, 13 Feb 2020, Matt Roper <matthew.d.roper@intel.com> wrote:
> On Thu, Feb 13, 2020 at 11:03:29PM +0200, Jani Nikula wrote:
>> On Thu, 13 Feb 2020, Matt Roper <matthew.d.roper@intel.com> wrote:
>> > On Thu, Feb 13, 2020 at 04:04:11PM +0200, Stanislav Lisovskiy wrote:
>> >> From: Jani Nikula <jani.nikula@intel.com>
>> >> 
>> >> We lack full state readout of DSC config, which may lead to DSC enable
>> >> using a config that's all zeros, failing spectacularly. Force full
>> >> modeset and thus compute config at probe to get a sane state, until we
>> >> implement DSC state readout. Any fastset that did appear to work with
>> >> DSC at probe, worked by coincidence. [1] is an example of a change that
>> >> triggered the issue on TGL DSI DSC.
>> >> 
>> >> [1] http://patchwork.freedesktop.org/patch/msgid/20200212150102.7600-1-ville.syrjala@linux.intel.com
>> >> 
>> >> Cc: Manasi Navare <manasi.d.navare@intel.com>
>> >> Cc: Vandita Kulkarni <vandita.kulkarni@intel.com>
>> >> Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
>> >> Cc: stable@vger.kernel.org
>> >> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
>> >
>> > Should this be
>> >
>> > Fixes: fbacb15ea814 ("drm/i915/dsc: add basic hardware state readout support")
>> >
>> > since that's where we added the basic readout with a FIXME to add more
>> > later?
>> 
>> That added some readout and checks, but the problem existed before them
>> too.
>
> Right, but that's as far back as we can go with a fix, right?  Since
> before that we don't even read out enough to know that compression is
> enabled?

Ah, that's right. Any fixes predating that commit would have to be
different. Perhaps we'll just settle for this. ;)

Thanks,
Jani.



>
>
> Matt
>
>> 
>> BR,
>> Jani.
>> 
>> 
>> 
>> >
>> > I don't know the specifics of DSC and what state we need, but the
>> > approach here seems reasonable.
>> >
>> > Acked-by: Matt Roper <matthew.d.roper@intel.com>
>> >
>> >> ---
>> >>  drivers/gpu/drm/i915/display/intel_display.c | 18 ++++++++++++++++++
>> >>  1 file changed, 18 insertions(+)
>> >> 
>> >> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
>> >> index 61ba1f2256a0..1e3f2cc27db8 100644
>> >> --- a/drivers/gpu/drm/i915/display/intel_display.c
>> >> +++ b/drivers/gpu/drm/i915/display/intel_display.c
>> >> @@ -17828,6 +17828,24 @@ static int intel_initial_commit(struct drm_device *dev)
>> >>  			 * have readout for pipe gamma enable.
>> >>  			 */
>> >>  			crtc_state->uapi.color_mgmt_changed = true;
>> >> +
>> >> +			/*
>> >> +			 * FIXME hack to force full modeset when DSC is being
>> >> +			 * used.
>> >> +			 *
>> >> +			 * As long as we do not have full state readout and
>> >> +			 * config comparison of crtc_state->dsc, we have no way
>> >> +			 * to ensure reliable fastset. Remove once we have
>> >> +			 * readout for DSC.
>> >> +			 */
>> >> +			if (crtc_state->dsc.compression_enable) {
>> >> +				ret = drm_atomic_add_affected_connectors(state,
>> >> +									 &crtc->base);
>> >> +				if (ret)
>> >> +					goto out;
>> >> +				crtc_state->uapi.mode_changed = true;
>> >> +				drm_dbg_kms(dev, "Force full modeset for DSC\n");
>> >> +			}
>> >>  		}
>> >>  	}
>> >>  
>> >> -- 
>> >> 2.24.1.485.gad05a3d8e5
>> >> 
>> >> _______________________________________________
>> >> Intel-gfx mailing list
>> >> Intel-gfx@lists.freedesktop.org
>> >> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
>> 
>> -- 
>> Jani Nikula, Intel Open Source Graphics Center
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index 61ba1f2256a0..1e3f2cc27db8 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -17828,6 +17828,24 @@  static int intel_initial_commit(struct drm_device *dev)
 			 * have readout for pipe gamma enable.
 			 */
 			crtc_state->uapi.color_mgmt_changed = true;
+
+			/*
+			 * FIXME hack to force full modeset when DSC is being
+			 * used.
+			 *
+			 * As long as we do not have full state readout and
+			 * config comparison of crtc_state->dsc, we have no way
+			 * to ensure reliable fastset. Remove once we have
+			 * readout for DSC.
+			 */
+			if (crtc_state->dsc.compression_enable) {
+				ret = drm_atomic_add_affected_connectors(state,
+									 &crtc->base);
+				if (ret)
+					goto out;
+				crtc_state->uapi.mode_changed = true;
+				drm_dbg_kms(dev, "Force full modeset for DSC\n");
+			}
 		}
 	}