summaryrefslogtreecommitdiffstats
path: root/drivers/gpu/drm/tegra/dsi.c
diff options
context:
space:
mode:
authorJon Hunter <jonathanh@nvidia.com>2016-05-18 16:37:36 +0100
committerDaniel Vetter <daniel.vetter@ffwll.ch>2016-05-18 18:03:33 +0200
commit280dc0e145b2b04fd1b414e512118ce6eb9b93e8 (patch)
tree996a94de2aa6415ad635a5f562e92e0b6184e9ea /drivers/gpu/drm/tegra/dsi.c
parentfdf2c85f26a656df3c9ef2114ff508a4be26bbff (diff)
downloadlinux-280dc0e145b2b04fd1b414e512118ce6eb9b93e8.tar.bz2
drm/tegra: Fix crash caused by reference count imbalance
Commit d2307dea14a4 ("drm/atomic: use connector references (v3)") added reference counting for DRM connectors and this caused a crash when exercising system suspend on Tegra114 Dalmore. The Tegra DSI driver implements a Tegra specific function, tegra_dsi_connector_duplicate_state(), to duplicate the connector state and destroys the state using the generic helper function, drm_atomic_helper_connector_destroy_state(). Following commit d2307dea14a4 ("drm/atomic: use connector references (v3)") there is now an imbalance in the connector reference count because the Tegra function to duplicate state does not take a reference when duplicating the state information. However, the generic helper function to destroy the state information assumes a reference has been taken and during system suspend, when the connector state is destroyed, this leads to a crash because we attempt to put the reference for an object that has already been freed. Fix this by calling __drm_atomic_helper_connector_duplicate_state() from tegra_dsi_connector_duplicate_state() to ensure that we take a reference on a connector if crtc is set. Note that this will also copy the connector state a 2nd time, but this should be harmless. By fixing tegra_dsi_connector_duplicate_state() to take a reference, although a crash was no longer seen, it was then observed that after each system suspend-resume cycle, the reference would be one greater than before the suspend-resume cycle. Following commit d2307dea14a4 ("drm/atomic: use connector references (v3)"), it was found that we also need to put the reference when calling the function tegra_dsi_connector_reset() before freeing the state. Fix this by updating tegra_dsi_connector_reset() to call the function __drm_atomic_helper_connector_destroy_state() in order to put the reference for the connector. Fixes: d2307dea14a4 ("drm/atomic: use connector references (v3)") Signed-off-by: Jon Hunter <jonathanh@nvidia.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Acked-by: Thierry Reding <treding@nvidia.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/1463585856-16606-1-git-send-email-jonathanh@nvidia.com
Diffstat (limited to 'drivers/gpu/drm/tegra/dsi.c')
-rw-r--r--drivers/gpu/drm/tegra/dsi.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/drivers/gpu/drm/tegra/dsi.c b/drivers/gpu/drm/tegra/dsi.c
index 44e102799195..d1239ebc190f 100644
--- a/drivers/gpu/drm/tegra/dsi.c
+++ b/drivers/gpu/drm/tegra/dsi.c
@@ -745,13 +745,17 @@ static void tegra_dsi_soft_reset(struct tegra_dsi *dsi)
static void tegra_dsi_connector_reset(struct drm_connector *connector)
{
- struct tegra_dsi_state *state =
- kzalloc(sizeof(*state), GFP_KERNEL);
+ struct tegra_dsi_state *state = kzalloc(sizeof(*state), GFP_KERNEL);
- if (state) {
+ if (!state)
+ return;
+
+ if (connector->state) {
+ __drm_atomic_helper_connector_destroy_state(connector->state);
kfree(connector->state);
- __drm_atomic_helper_connector_reset(connector, &state->base);
}
+
+ __drm_atomic_helper_connector_reset(connector, &state->base);
}
static struct drm_connector_state *
@@ -764,6 +768,9 @@ tegra_dsi_connector_duplicate_state(struct drm_connector *connector)
if (!copy)
return NULL;
+ __drm_atomic_helper_connector_duplicate_state(connector,
+ &copy->base);
+
return &copy->base;
}