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: 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>
diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index 2efaf8e..e8abfce 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -699,16 +699,21 @@
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;