[PATCH v2 1/2] drm/i915: Prevent HW access during init from SDVO TV get_modes hook

[Imre Deak]

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 at intel.com>
Reviewed-by: Jouni Högander <jouni.hogander at intel.com>
---
 drivers/gpu/drm/i915/display/intel_sdvo.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_sdvo.c b/drivers/gpu/drm/i915/display/intel_sdvo.c
index 2571ef5a1b211..ccea0efbd136f 100644
--- a/drivers/gpu/drm/i915/display/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/display/intel_sdvo.c
@@ -2287,6 +2287,7 @@ static const struct drm_display_mode sdvo_tv_modes[] = {
 static int intel_sdvo_get_tv_modes(struct drm_connector *connector)
 {
 	struct intel_sdvo *intel_sdvo = intel_attached_sdvo(to_intel_connector(connector));
+	struct drm_i915_private *i915 = to_i915(intel_sdvo->base.base.dev);
 	struct intel_sdvo_connector *intel_sdvo_connector =
 		to_intel_sdvo_connector(connector);
 	const struct drm_connector_state *conn_state = connector->state;
@@ -2298,6 +2299,9 @@ static int intel_sdvo_get_tv_modes(struct drm_connector *connector)
 	DRM_DEBUG_KMS("[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.
-- 
2.39.2