From 3a86cb16ab329b235ecd26adce584e5cb0c808d4 Mon Sep 17 00:00:00 2001 From: Imre Deak Date: Mon, 12 Feb 2024 19:52:37 +0200 Subject: drm/i915: Prevent HW access during init from connector get_modes hooks MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Prevent accessing the HW from the get_modes hooks of connectors deriving the mode list from the display's EDID. drm_edid_connector_add_modes() will return the mode list based on the EDID which was cached during a previous detection/get_modes call. This also fixes the NULL deref problem (10085) which was introduced/revealed by commit bab87ef4db9a ("drm/i915: Disable hotplug detection handlers during driver init/shutdown") After the above change MST connectors will not change state during driver init/shutdown; thus some of these connectors with no I2C/DDC adapter registered for them (since the given MST port has no sink connected) may stay then in the 'unknown' connector status. The get_modes() hook should not try to use the I2C/DDC adapter in this state (which would lead to the above NULL deref) which this patch ensures. v2: - Remove the redundant check from intel_crt_ddc_get_modes(). - Rebase on latest drm-tip. - Add Fixes: line / related commit notes. Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/10085 Fixes: bab87ef4db9a ("drm/i915: Disable hotplug detection handlers during driver init/shutdown") Signed-off-by: Imre Deak Reviewed-by: Jouni Högander Link: https://patchwork.freedesktop.org/patch/msgid/20240212175237.2625812-2-imre.deak@intel.com --- drivers/gpu/drm/i915/display/intel_crt.c | 3 +++ drivers/gpu/drm/i915/display/intel_dp_mst.c | 4 ++++ drivers/gpu/drm/i915/display/intel_dvo.c | 5 +++++ drivers/gpu/drm/i915/display/intel_sdvo.c | 4 ++++ 4 files changed, 16 insertions(+) diff --git a/drivers/gpu/drm/i915/display/intel_crt.c b/drivers/gpu/drm/i915/display/intel_crt.c index b9733a73e21d..93479db0f89f 100644 --- a/drivers/gpu/drm/i915/display/intel_crt.c +++ b/drivers/gpu/drm/i915/display/intel_crt.c @@ -933,6 +933,9 @@ static int intel_crt_get_modes(struct drm_connector *connector) struct i2c_adapter *ddc; int ret; + if (!intel_display_driver_check_access(dev_priv)) + return drm_edid_connector_add_modes(connector); + wakeref = intel_display_power_get(dev_priv, intel_encoder->power_domain); diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c index 5fa25a5a36b5..5307ddd4edcf 100644 --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c @@ -1197,6 +1197,7 @@ static bool intel_dp_mst_initial_fastset_check(struct intel_encoder *encoder, static int intel_dp_mst_get_ddc_modes(struct drm_connector *connector) { struct intel_connector *intel_connector = to_intel_connector(connector); + struct drm_i915_private *i915 = to_i915(intel_connector->base.dev); struct intel_dp *intel_dp = intel_connector->mst_port; const struct drm_edid *drm_edid; int ret; @@ -1204,6 +1205,9 @@ static int intel_dp_mst_get_ddc_modes(struct drm_connector *connector) if (drm_connector_is_unregistered(connector)) return intel_connector_update_modes(connector, NULL); + if (!intel_display_driver_check_access(i915)) + return drm_edid_connector_add_modes(connector); + drm_edid = drm_dp_mst_edid_read(connector, &intel_dp->mst_mgr, intel_connector->port); ret = intel_connector_update_modes(connector, drm_edid); diff --git a/drivers/gpu/drm/i915/display/intel_dvo.c b/drivers/gpu/drm/i915/display/intel_dvo.c index 8ca9ae4798a8..c076da75b066 100644 --- a/drivers/gpu/drm/i915/display/intel_dvo.c +++ b/drivers/gpu/drm/i915/display/intel_dvo.c @@ -30,6 +30,7 @@ #include #include +#include #include "i915_drv.h" #include "i915_reg.h" @@ -338,8 +339,12 @@ intel_dvo_detect(struct drm_connector *_connector, bool force) static int intel_dvo_get_modes(struct drm_connector *_connector) { struct intel_connector *connector = to_intel_connector(_connector); + struct drm_i915_private *i915 = to_i915(connector->base.dev); int num_modes; + if (!intel_display_driver_check_access(i915)) + return drm_edid_connector_add_modes(&connector->base); + /* * We should probably have an i2c driver get_modes function for those * devices which will have a fixed set of modes determined by the chip diff --git a/drivers/gpu/drm/i915/display/intel_sdvo.c b/drivers/gpu/drm/i915/display/intel_sdvo.c index eb65c8124e60..3b79488357ba 100644 --- a/drivers/gpu/drm/i915/display/intel_sdvo.c +++ b/drivers/gpu/drm/i915/display/intel_sdvo.c @@ -2202,12 +2202,16 @@ intel_sdvo_detect(struct drm_connector *connector, bool force) static int intel_sdvo_get_ddc_modes(struct drm_connector *connector) { + struct drm_i915_private *i915 = to_i915(connector->dev); int num_modes = 0; const struct drm_edid *drm_edid; drm_dbg_kms(connector->dev, "[CONNECTOR:%d:%s]\n", connector->base.id, connector->name); + if (!intel_display_driver_check_access(i915)) + return drm_edid_connector_add_modes(connector); + /* set the bus switch and get the modes */ drm_edid = intel_sdvo_get_edid(connector); -- cgit