[0505/1094] drm/i915: add locking to fixed panel edid probing

Commit Message

Dheeraj Jamwal Oct. 21, 2014, 10:51 a.m. UTC

From: Daniel Vetter <[e-mail]>

With the recent addition of locking checks in

commit 62ff94a5492175759546f8bc61383189d6b49122
Author:     Daniel Vetter <[e-mail]>
AuthorDate: Thu Jan 23 22:18:47 2014 +0100

    drm/crtc-helper: remove LOCKING from kerneldoc

drm_add_edid_modes started to WARN about the mode_config.mutex not
being held in the lvds and dp initialization code.

Now since this is init code locking is fairly redudant if it wouldn't
be for the drm core registering sysfs files a bit early. And the
locking WARNINGs nicely enforce that indeed all access to the mode
lists are properly protected. And a full audit shows that only i915
and gma500 touch the modes lists at init time.

Hence I've opted to wrap up this entire mode detection sequence for
fixed panels with the mode_config mutex for both lvds and edp outputs.

Signed-off-by: Daniel Vetter <[e-mail]>
Signed-off-by: Dave Airlie <[e-mail]>
(cherry picked from commit 060c877848b8a0a44d7ba32ff3a53982a6e907f7)

Conflicts:

	drivers/gpu/drm/i915/intel_dp.c
Signed-off-by: Dheeraj Jamwal <[e-mail]>
---
 drivers/gpu/drm/i915/intel_dp.c   |    2 ++
 drivers/gpu/drm/i915/intel_lvds.c |    5 +++++
 2 files changed, 7 insertions(+)

Patch

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index df1fff5..54ae22e 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -3646,6 +3646,7 @@  static bool intel_edp_init_connector(struct intel_dp *intel_dp,
 	/* We now know it's not a ghost, init power sequence regs. */
 	intel_dp_init_panel_power_sequencer_registers(dev, intel_dp, power_seq);
 
+	mutex_lock(&dev->mode_config.mutex);
 	edid = drm_get_edid(connector, &intel_dp->aux.ddc);
 	if (edid) {
 		if (drm_add_edid_modes(connector, edid)) {
@@ -3676,6 +3677,7 @@  static bool intel_edp_init_connector(struct intel_dp *intel_dp,
 		if (fixed_mode)
 			fixed_mode->type |= DRM_MODE_TYPE_PREFERRED;
 	}
+	mutex_unlock(&dev->mode_config.mutex);
 
 	intel_panel_init(&intel_connector->panel, fixed_mode, NULL);
 	intel_panel_setup_backlight(connector);
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index ef5e566..f1ecf91 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -1002,6 +1002,7 @@  void intel_lvds_init(struct drm_device *dev)
 	 * Attempt to get the fixed panel mode from DDC.  Assume that the
 	 * preferred mode is the right one.
 	 */
+	mutex_lock(&dev->mode_config.mutex);
 	edid = drm_get_edid(connector, intel_gmbus_get_adapter(dev_priv, pin));
 	if (edid) {
 		if (drm_add_edid_modes(connector, edid)) {
@@ -1095,6 +1096,8 @@  void intel_lvds_init(struct drm_device *dev)
 		goto failed;
 
 out:
+	mutex_unlock(&dev->mode_config.mutex);
+
 	lvds_encoder->is_dual_link = compute_is_dual_link_lvds(lvds_encoder);
 	DRM_DEBUG_KMS("detected %s-link lvds configuration\n",
 		      lvds_encoder->is_dual_link ? "dual" : "single");
@@ -1123,6 +1126,8 @@  out:
 	return;
 
 failed:
+	mutex_unlock(&dev->mode_config.mutex);
+
 	DRM_DEBUG_KMS("No LVDS modes found, disabling.\n");
 	drm_connector_cleanup(connector);
 	drm_encoder_cleanup(encoder);