drm/i915: Prevent HW access during init from SDVO TV get_modes hook

Prevent accessing the HW from the SDVO/TV get_modes connector hook.
Returning 0 from the hook will make the caller -
drm_helper_probe_single_connector_modes() - return a default/EDID
override mode list to users. This matches the case where
intel_sdvo_get_tv_modes() fails to retrieve the current mode list due to
a HW access failure.

v2: Clarify the commit message wrt. which modes get_modes() returns. (Jouni)

Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240212175237.2625812-1-imre.deak@intel.com

diff --git a/drivers/gpu/drm/i915/display/intel_sdvo.c b/drivers/gpu/drm/i915/display/intel_sdvo.c
index 66dab0a37e65d0e0ca8e271481e49f499635820c..eb65c8124e60a979a62019442b23241a0b6d6f4e 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/display/intel_sdvo.c
@@ -2312,6 +2312,9 @@ static int intel_sdvo_get_tv_modes(struct drm_connector *connector)
        drm_dbg_kms(&i915->drm, "[CONNECTOR:%d:%s]\n",
                    connector->base.id, connector->name);
 
+       if (!intel_display_driver_check_access(i915))
+               return 0;
+
        /*
         * Read the list of supported input resolutions for the selected TV
         * format.