drm/fb-helper: Stop using mode_config.mutex for internals

Those are now all protected using fb_helper->lock.

v2: We still need to hold mode_config.mutex right around calling
connector->fill_modes.

v3: I forgot to hold mode_config.mutex while looking at
connector->status and the mode list. Also, we need to patch up the
i915 ->initial_config callback to grab the locks it needs to inspect
the modeset state recovered from the fw.

v4: Don't reorder the probe too much (Ville).

Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Thierry Reding <treding@nvidia.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170705045629.31265-1-daniel.vetter@ffwll.ch

1 files changed, 12 insertions, 4 deletions

diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
index 03347c6ae599..460ca0b3fb88 100644
--- a/drivers/gpu/drm/i915/intel_fbdev.c
+++ b/drivers/gpu/drm/i915/intel_fbdev.c
@@ -352,14 +352,20 @@ static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
 	unsigned int count = min(fb_helper->connector_count, BITS_PER_LONG);
 	int i, j;
 	bool *save_enabled;
-	bool fallback = true;
+	bool fallback = true, ret = true;
 	int num_connectors_enabled = 0;
 	int num_connectors_detected = 0;
+	struct drm_modeset_acquire_ctx ctx;
 
 	save_enabled = kcalloc(count, sizeof(bool), GFP_KERNEL);
 	if (!save_enabled)
 		return false;
 
+	drm_modeset_acquire_init(&ctx, 0);
+
+	while (drm_modeset_lock_all_ctx(fb_helper->dev, &ctx) != 0)
+		drm_modeset_backoff(&ctx);
+
 	memcpy(save_enabled, enabled, count);
 	mask = GENMASK(count - 1, 0);
 	conn_configured = 0;
@@ -509,12 +515,14 @@ retry:
 bail:
 		DRM_DEBUG_KMS("Not using firmware configuration\n");
 		memcpy(enabled, save_enabled, count);
-		kfree(save_enabled);
-		return false;
+		ret = false;
 	}
 
+	drm_modeset_drop_locks(&ctx);
+	drm_modeset_acquire_fini(&ctx);
+
 	kfree(save_enabled);
-	return true;
+	return ret;
 }
 
 static const struct drm_fb_helper_funcs intel_fb_helper_funcs = {