drm/i915: add locking to fixed panel edid probing

With the recent addition of locking checks in

commit 62ff94a5492175759546f8bc61383189d6b49122
Author:     Daniel Vetter <daniel.vetter@ffwll.ch>
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 <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index bbb1327644d48b923bcf1e99a8087929095667ef..7ca38e11e6955465445224961027b1547b3324ba 100644 (file)
--- 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 ef5e5661efb21f3ade3da94e52ac47f1c86af5fc..f1ecf916474a93e3a18dd604991a8915309d83cb 100644 (file)
--- 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 @@ void intel_lvds_init(struct drm_device *dev)
        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);