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Commit 208bf9fd authored by Ville Syrjälä's avatar Ville Syrjälä Committed by Jani Nikula
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drm/i915: Fix locking for intel_enable_pipe_a() 



intel_enable_pipe_a() gets called with all the modeset locks already
held (by drm_modeset_lock_all()), so trying to grab the same
locks using another drm_modeset_acquire_ctx is going to fail miserably.

Move most of the drm_modeset_acquire_ctx handling (init/drop/fini)
out from intel_{get,release}_load_detect_pipe() into the callers
(intel_{crt,tv}_detect()). Only the actual locking and backoff
handling is left in intel_get_load_detect_pipe(). And in
intel_enable_pipe_a() we just share the mode_config.acquire_ctx from
drm_modeset_lock_all() which is already holding all the relevant locks.

It's perfectly legal to lock the same ww_mutex multiple times using the
same ww_acquire_ctx. drm_modeset_lock() will convert the returned
-EALREADY into 0, so the caller doesn't need to do antyhing special.

Fixes a hang on resume on my 830.

Signed-off-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
parent 7d1311b9

drivers/gpu/drm/i915/intel_crt.c

+6 −1
Original line number Diff line number Diff line
@@ -699,16 +699,21 @@ intel_crt_detect(struct drm_connector *connector, bool force) 
		goto out;

	}



	drm_modeset_acquire_init(&ctx, 0);



	/* for pre-945g platforms use load detect */

	if (intel_get_load_detect_pipe(connector, NULL, &tmp, &ctx)) {

		if (intel_crt_detect_ddc(connector))

			status = connector_status_connected;

		else

			status = intel_crt_load_detect(crt);

		intel_release_load_detect_pipe(connector, &tmp, &ctx);

		intel_release_load_detect_pipe(connector, &tmp);

	} else

		status = connector_status_unknown;



	drm_modeset_drop_locks(&ctx);

	drm_modeset_acquire_fini(&ctx);



out:

	intel_display_power_put(dev_priv, power_domain);

	return status;

drivers/gpu/drm/i915/intel_display.c

+4 −17
Original line number Diff line number Diff line
@@ -8462,8 +8462,6 @@ bool intel_get_load_detect_pipe(struct drm_connector *connector, 
		      connector->base.id, connector->name,

		      encoder->base.id, encoder->name);



	drm_modeset_acquire_init(ctx, 0);



retry:

	ret = drm_modeset_lock(&config->connection_mutex, ctx);

	if (ret)
@@ -8574,15 +8572,11 @@ bool intel_get_load_detect_pipe(struct drm_connector *connector, 
		goto retry;

	}



	drm_modeset_drop_locks(ctx);

	drm_modeset_acquire_fini(ctx);



	return false;

}



void intel_release_load_detect_pipe(struct drm_connector *connector,

				    struct intel_load_detect_pipe *old,

				    struct drm_modeset_acquire_ctx *ctx)

				    struct intel_load_detect_pipe *old)

{

	struct intel_encoder *intel_encoder =

		intel_attached_encoder(connector);
@@ -8606,17 +8600,12 @@ void intel_release_load_detect_pipe(struct drm_connector *connector, 
			drm_framebuffer_unreference(old->release_fb);

		}



		goto unlock;

		return;

	}



	/* Switch crtc and encoder back off if necessary */

	if (old->dpms_mode != DRM_MODE_DPMS_ON)

		connector->funcs->dpms(connector, old->dpms_mode);



unlock:

	drm_modeset_drop_locks(ctx);

	drm_modeset_acquire_fini(ctx);

}



static int i9xx_pll_refclk(struct drm_device *dev,
@@ -12659,7 +12648,7 @@ static void intel_enable_pipe_a(struct drm_device *dev) 
	struct intel_connector *connector;

	struct drm_connector *crt = NULL;

	struct intel_load_detect_pipe load_detect_temp;

	struct drm_modeset_acquire_ctx ctx;

	struct drm_modeset_acquire_ctx *ctx = dev->mode_config.acquire_ctx;



	/* We can't just switch on the pipe A, we need to set things up with a

	 * proper mode and output configuration. As a gross hack, enable pipe A
@@ -12676,10 +12665,8 @@ static void intel_enable_pipe_a(struct drm_device *dev) 
	if (!crt)

		return;



	if (intel_get_load_detect_pipe(crt, NULL, &load_detect_temp, &ctx))

		intel_release_load_detect_pipe(crt, &load_detect_temp, &ctx);





	if (intel_get_load_detect_pipe(crt, NULL, &load_detect_temp, ctx))

		intel_release_load_detect_pipe(crt, &load_detect_temp);

}



static bool

drivers/gpu/drm/i915/intel_drv.h

+1 −2
Original line number Diff line number Diff line
@@ -830,8 +830,7 @@ bool intel_get_load_detect_pipe(struct drm_connector *connector, 
				struct intel_load_detect_pipe *old,

				struct drm_modeset_acquire_ctx *ctx);

void intel_release_load_detect_pipe(struct drm_connector *connector,

				    struct intel_load_detect_pipe *old,

				    struct drm_modeset_acquire_ctx *ctx);

				    struct intel_load_detect_pipe *old);

int intel_pin_and_fence_fb_obj(struct drm_device *dev,

			       struct drm_i915_gem_object *obj,

			       struct intel_engine_cs *pipelined);

drivers/gpu/drm/i915/intel_tv.c

+6 −1
Original line number Diff line number Diff line
@@ -1323,11 +1323,16 @@ intel_tv_detect(struct drm_connector *connector, bool force) 
		struct intel_load_detect_pipe tmp;

		struct drm_modeset_acquire_ctx ctx;



		drm_modeset_acquire_init(&ctx, 0);



		if (intel_get_load_detect_pipe(connector, &mode, &tmp, &ctx)) {

			type = intel_tv_detect_type(intel_tv, connector);

			intel_release_load_detect_pipe(connector, &tmp, &ctx);

			intel_release_load_detect_pipe(connector, &tmp);

		} else

			return connector_status_unknown;



		drm_modeset_drop_locks(&ctx);

		drm_modeset_acquire_fini(&ctx);

	} else

		return connector->status;