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[PATCH v4 2/4] drm/atomic-helper: Introduce drm_atomic_helper_reset_crtc()

Herve Codina posted 4 patches 1 year ago
There is a newer version of this series
[PATCH v4 2/4] drm/atomic-helper: Introduce drm_atomic_helper_reset_crtc()
Posted by Herve Codina 1 year ago 
drm_atomic_helper_reset_crtc() allows to reset the CRTC active outputs.

This resets all active components available between the CRTC and
connectors.

Signed-off-by: Herve Codina <herve.codina@bootlin.com>
---
 drivers/gpu/drm/drm_atomic_helper.c | 41 +++++++++++++++++++++++++++++
 include/drm/drm_atomic_helper.h     |  2 ++
 2 files changed, 43 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
index 8ed186ddaeaf..cac807df8a86 100644
--- a/drivers/gpu/drm/drm_atomic_helper.c
+++ b/drivers/gpu/drm/drm_atomic_helper.c
@@ -3363,6 +3363,47 @@ int drm_atomic_helper_disable_all(struct drm_device *dev,
 }
 EXPORT_SYMBOL(drm_atomic_helper_disable_all);
 
+/**
+ * drm_atomic_helper_reset_crtc - reset the active outputs of a CRTC
+ * @crtc: DRM CRTC
+ * @ctx: lock acquisition context
+ *
+ * Reset the active outputs by indicating that connectors have changed.
+ * This implies a reset of all active components available between the CRTC and
+ * connectors.
+ *
+ * Returns:
+ * 0 on success or a negative error code on failure.
+ */
+int drm_atomic_helper_reset_crtc(struct drm_crtc *crtc,
+				 struct drm_modeset_acquire_ctx *ctx)
+{
+	struct drm_atomic_state *state;
+	struct drm_crtc_state *crtc_state;
+	int ret;
+
+	state = drm_atomic_state_alloc(crtc->dev);
+	if (!state)
+		return -ENOMEM;
+
+	state->acquire_ctx = ctx;
+
+	crtc_state = drm_atomic_get_crtc_state(state, crtc);
+	if (IS_ERR(crtc_state)) {
+		ret = PTR_ERR(crtc_state);
+		goto out;
+	}
+
+	crtc_state->connectors_changed = true;
+
+	ret = drm_atomic_commit(state);
+out:
+	drm_atomic_state_put(state);
+
+	return ret;
+}
+EXPORT_SYMBOL(drm_atomic_helper_reset_crtc);
+
 /**
  * drm_atomic_helper_shutdown - shutdown all CRTC
  * @dev: DRM device
diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
index 9aa0a05aa072..53382fe93537 100644
--- a/include/drm/drm_atomic_helper.h
+++ b/include/drm/drm_atomic_helper.h
@@ -139,6 +139,8 @@ int drm_atomic_helper_set_config(struct drm_mode_set *set,
 
 int drm_atomic_helper_disable_all(struct drm_device *dev,
 				  struct drm_modeset_acquire_ctx *ctx);
+int drm_atomic_helper_reset_crtc(struct drm_crtc *crtc,
+				 struct drm_modeset_acquire_ctx *ctx);
 void drm_atomic_helper_shutdown(struct drm_device *dev);
 struct drm_atomic_state *
 drm_atomic_helper_duplicate_state(struct drm_device *dev,
-- 
2.47.1
Re: [PATCH v4 2/4] drm/atomic-helper: Introduce drm_atomic_helper_reset_crtc()
Posted by Simona Vetter 11 months, 3 weeks ago 
On Mon, Feb 03, 2025 at 03:58:21PM +0100, Herve Codina wrote:
> drm_atomic_helper_reset_crtc() allows to reset the CRTC active outputs.
> 
> This resets all active components available between the CRTC and
> connectors.
> 
> Signed-off-by: Herve Codina <herve.codina@bootlin.com>
> ---
>  drivers/gpu/drm/drm_atomic_helper.c | 41 +++++++++++++++++++++++++++++
>  include/drm/drm_atomic_helper.h     |  2 ++
>  2 files changed, 43 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> index 8ed186ddaeaf..cac807df8a86 100644
> --- a/drivers/gpu/drm/drm_atomic_helper.c
> +++ b/drivers/gpu/drm/drm_atomic_helper.c
> @@ -3363,6 +3363,47 @@ int drm_atomic_helper_disable_all(struct drm_device *dev,
>  }
>  EXPORT_SYMBOL(drm_atomic_helper_disable_all);
>  
> +/**
> + * drm_atomic_helper_reset_crtc - reset the active outputs of a CRTC
> + * @crtc: DRM CRTC
> + * @ctx: lock acquisition context
> + *
> + * Reset the active outputs by indicating that connectors have changed.
> + * This implies a reset of all active components available between the CRTC and
> + * connectors.

I think you definitely want a

	Note: This relies on resetting &drm_crtc_state.connectors_changed.
	For drivers which optimize out unnecessary modesets this will
	result in a no-op commit, achieving nothing.

> + *
> + * Returns:
> + * 0 on success or a negative error code on failure.
> + */
> +int drm_atomic_helper_reset_crtc(struct drm_crtc *crtc,
> +				 struct drm_modeset_acquire_ctx *ctx)

So this is pretty close to DP drivers doing link-retraining when
reconnecting a cable. Would be really nice if that could also be rolled
out there where it fits, and maybe augment the documentation accordingly
so that dp helpers point at this?

Either way would be good to extend the kerneldoc a bit to explain what
this is good for. Either way.

Acked-by: Simona Vetter <simona.vetter@ffwll.ch>

Cheers, Sima
> +{
> +	struct drm_atomic_state *state;
> +	struct drm_crtc_state *crtc_state;
> +	int ret;
> +
> +	state = drm_atomic_state_alloc(crtc->dev);
> +	if (!state)
> +		return -ENOMEM;
> +
> +	state->acquire_ctx = ctx;
> +
> +	crtc_state = drm_atomic_get_crtc_state(state, crtc);
> +	if (IS_ERR(crtc_state)) {
> +		ret = PTR_ERR(crtc_state);
> +		goto out;
> +	}
> +
> +	crtc_state->connectors_changed = true;
> +
> +	ret = drm_atomic_commit(state);
> +out:
> +	drm_atomic_state_put(state);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL(drm_atomic_helper_reset_crtc);
> +
>  /**
>   * drm_atomic_helper_shutdown - shutdown all CRTC
>   * @dev: DRM device
> diff --git a/include/drm/drm_atomic_helper.h b/include/drm/drm_atomic_helper.h
> index 9aa0a05aa072..53382fe93537 100644
> --- a/include/drm/drm_atomic_helper.h
> +++ b/include/drm/drm_atomic_helper.h
> @@ -139,6 +139,8 @@ int drm_atomic_helper_set_config(struct drm_mode_set *set,
>  
>  int drm_atomic_helper_disable_all(struct drm_device *dev,
>  				  struct drm_modeset_acquire_ctx *ctx);
> +int drm_atomic_helper_reset_crtc(struct drm_crtc *crtc,
> +				 struct drm_modeset_acquire_ctx *ctx);
>  void drm_atomic_helper_shutdown(struct drm_device *dev);
>  struct drm_atomic_state *
>  drm_atomic_helper_duplicate_state(struct drm_device *dev,
> -- 
> 2.47.1
> 

-- 
Simona Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
Re: [PATCH v4 2/4] drm/atomic-helper: Introduce drm_atomic_helper_reset_crtc()
Posted by Maxime Ripard 11 months, 3 weeks ago 
On Wed, Feb 19, 2025 at 02:41:48PM +0100, Simona Vetter wrote:
> On Mon, Feb 03, 2025 at 03:58:21PM +0100, Herve Codina wrote:
> > drm_atomic_helper_reset_crtc() allows to reset the CRTC active outputs.
> > 
> > This resets all active components available between the CRTC and
> > connectors.
> > 
> > Signed-off-by: Herve Codina <herve.codina@bootlin.com>
> > ---
> >  drivers/gpu/drm/drm_atomic_helper.c | 41 +++++++++++++++++++++++++++++
> >  include/drm/drm_atomic_helper.h     |  2 ++
> >  2 files changed, 43 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c
> > index 8ed186ddaeaf..cac807df8a86 100644
> > --- a/drivers/gpu/drm/drm_atomic_helper.c
> > +++ b/drivers/gpu/drm/drm_atomic_helper.c
> > @@ -3363,6 +3363,47 @@ int drm_atomic_helper_disable_all(struct drm_device *dev,
> >  }
> >  EXPORT_SYMBOL(drm_atomic_helper_disable_all);
> >  
> > +/**
> > + * drm_atomic_helper_reset_crtc - reset the active outputs of a CRTC
> > + * @crtc: DRM CRTC
> > + * @ctx: lock acquisition context
> > + *
> > + * Reset the active outputs by indicating that connectors have changed.
> > + * This implies a reset of all active components available between the CRTC and
> > + * connectors.
> 
> I think you definitely want a
> 
> 	Note: This relies on resetting &drm_crtc_state.connectors_changed.
> 	For drivers which optimize out unnecessary modesets this will
> 	result in a no-op commit, achieving nothing.
> 
> > + *
> > + * Returns:
> > + * 0 on success or a negative error code on failure.
> > + */
> > +int drm_atomic_helper_reset_crtc(struct drm_crtc *crtc,
> > +				 struct drm_modeset_acquire_ctx *ctx)
> 
> So this is pretty close to DP drivers doing link-retraining when
> reconnecting a cable. Would be really nice if that could also be rolled
> out there where it fits, and maybe augment the documentation accordingly
> so that dp helpers point at this?

Given that the patch is already merged, Herve, could you send a
subsequent patch fixing up the doc at least?

Thanks,
Maxime
Re: [PATCH v4 2/4] drm/atomic-helper: Introduce drm_atomic_helper_reset_crtc()
Posted by Herve Codina 11 months, 3 weeks ago 
Hi Maxime,

On Thu, 20 Feb 2025 11:44:37 +0100
Maxime Ripard <mripard@kernel.org> wrote:

...
> 
> Given that the patch is already merged, Herve, could you send a
> subsequent patch fixing up the doc at least?

Did the patch:
  https://lore.kernel.org/all/20250220140406.593314-1-herve.codina@bootlin.com/

Best regards,
Hervé
Re: [PATCH v4 2/4] drm/atomic-helper: Introduce drm_atomic_helper_reset_crtc()
Posted by Dmitry Baryshkov 1 year ago 
On Mon, Feb 03, 2025 at 03:58:21PM +0100, Herve Codina wrote:
> drm_atomic_helper_reset_crtc() allows to reset the CRTC active outputs.
> 
> This resets all active components available between the CRTC and
> connectors.
> 
> Signed-off-by: Herve Codina <herve.codina@bootlin.com>
> ---
>  drivers/gpu/drm/drm_atomic_helper.c | 41 +++++++++++++++++++++++++++++
>  include/drm/drm_atomic_helper.h     |  2 ++
>  2 files changed, 43 insertions(+)
> 

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

-- 
With best wishes
Dmitry
Re: [PATCH v4 2/4] drm/atomic-helper: Introduce drm_atomic_helper_reset_crtc()
Posted by Herve Codina 1 year ago 
Hi Dmitry,

On Mon, 3 Feb 2025 17:56:33 +0200
Dmitry Baryshkov <dmitry.baryshkov@linaro.org> wrote:

> On Mon, Feb 03, 2025 at 03:58:21PM +0100, Herve Codina wrote:
> > drm_atomic_helper_reset_crtc() allows to reset the CRTC active outputs.
> > 
> > This resets all active components available between the CRTC and
> > connectors.
> > 
> > Signed-off-by: Herve Codina <herve.codina@bootlin.com>
> > ---
> >  drivers/gpu/drm/drm_atomic_helper.c | 41 +++++++++++++++++++++++++++++
> >  include/drm/drm_atomic_helper.h     |  2 ++
> >  2 files changed, 43 insertions(+)
> >   
> 
> Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> 

I messed me up in this v4. It doesn't apply on top of v6.14-rc1.

I already sent a v5 to fix that.

Can you add your tag on the v5?

Of course, I will add them myself if a v6 is needed.

I am sorry about my mistake.
Apologies,
Hervé


-- 
Hervé Codina, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

Patchew 2.1-devel-b67e4c2

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