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[v4,5/5] drm/i915: Fix intel_dp_mst_best_encoder()

Message ID 20181005002956.7317-6-lyude@redhat.com (mailing list archive)
State New, archived
Headers show
Series Fix legacy DPMS changes with MST | expand

Commit Message

Lyude Paul Oct. 5, 2018, 12:29 a.m. UTC 
Currently, i915 appears to rely on blocking modesets on
no-longer-present MSTB ports by simply returning NULL for
->best_encoder(), which in turn causes any new atomic commits that don't
disable the CRTC to fail. This is wrong however, since we still want to
allow userspace to disable CRTCs on no-longer-present MSTB ports by
changing the DPMS state to off and this still requires that we retrieve
an encoder.

So, fix this by always returning a valid encoder regardless of the state
of the MST port.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: stable@vger.kernel.org

Changes since v1:
- Remove mst atomic helper, since this got replaced with a much simpler
  solution

Signed-off-by: Lyude Paul <lyude@redhat.com>
---
 drivers/gpu/drm/i915/intel_dp_mst.c | 2 --
 1 file changed, 2 deletions(-)

Comments

Daniel Vetter Oct. 5, 2018, 7:28 a.m. UTC | #1 
On Thu, Oct 04, 2018 at 08:29:54PM -0400, Lyude Paul wrote:
> Currently, i915 appears to rely on blocking modesets on
> no-longer-present MSTB ports by simply returning NULL for
> ->best_encoder(), which in turn causes any new atomic commits that don't
> disable the CRTC to fail. This is wrong however, since we still want to
> allow userspace to disable CRTCs on no-longer-present MSTB ports by
> changing the DPMS state to off and this still requires that we retrieve
> an encoder.
> 
> So, fix this by always returning a valid encoder regardless of the state
> of the MST port.
> 
> Signed-off-by: Lyude Paul <lyude@redhat.com>
> Cc: stable@vger.kernel.org
> 
> Changes since v1:
> - Remove mst atomic helper, since this got replaced with a much simpler
>   solution
> 
> Signed-off-by: Lyude Paul <lyude@redhat.com>

With the obvious rebase onto my bikeshed for patch 3:

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> ---
>  drivers/gpu/drm/i915/intel_dp_mst.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
> index a366f32b048a..daade60c5714 100644
> --- a/drivers/gpu/drm/i915/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/intel_dp_mst.c
> @@ -407,8 +407,6 @@ static struct drm_encoder *intel_mst_atomic_best_encoder(struct drm_connector *c
>  	struct intel_dp *intel_dp = intel_connector->mst_port;
>  	struct intel_crtc *crtc = to_intel_crtc(state->crtc);
>  
> -	if (intel_connector->mst_port_gone)
> -		return NULL;
>  	return &intel_dp->mst_encoders[crtc->pipe]->base.base;
>  }
>  
> -- 
> 2.17.1
>
diff mbox series

Patch

diff --git a/drivers/gpu/drm/i915/intel_dp_mst.c b/drivers/gpu/drm/i915/intel_dp_mst.c
index a366f32b048a..daade60c5714 100644
--- a/drivers/gpu/drm/i915/intel_dp_mst.c
+++ b/drivers/gpu/drm/i915/intel_dp_mst.c
@@ -407,8 +407,6 @@  static struct drm_encoder *intel_mst_atomic_best_encoder(struct drm_connector *c
 	struct intel_dp *intel_dp = intel_connector->mst_port;
 	struct intel_crtc *crtc = to_intel_crtc(state->crtc);
 
-	if (intel_connector->mst_port_gone)
-		return NULL;
 	return &intel_dp->mst_encoders[crtc->pipe]->base.base;
 }