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drm/i915: Fix locking for intel_enable_pipe_a()

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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: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: stable@vger.kernel.org
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
This commit is contained in:
Ville Syrjälä 2014-08-11 13:15:35 +03:00 committed by Jani Nikula
parent 7d1311b93e
commit 208bf9fdcd
4 changed files with 17 additions and 21 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/gpu/drm/i915/intel_crt.c
View File

@ -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;

21
drivers/gpu/drm/i915/intel_display.c
View File

@ -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

3
drivers/gpu/drm/i915/intel_drv.h
View File

@ -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);

7
drivers/gpu/drm/i915/intel_tv.c
View File

@ -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;