drm/i915/sdvo: Handle unsupported GET_SUPPORTED_ENHANCEMENTS gracefully

In the event that the external chipset doesn't implement the
GET_SUPPORTED_ENHANCEMENTS commands, gracefully treat it as having no
enhancments rather than bailing.

Reported-and-tested-by: Woody Suwalski <terraluna977@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=18342
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 4 insertions, 5 deletions

diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index 60fcef700be6..ee73e428a84a 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -2520,11 +2520,10 @@ static bool intel_sdvo_create_enhance_property(struct intel_sdvo *intel_sdvo,
                 uint16_t response;
         } enhancements;
 
-        if (!intel_sdvo_get_value(intel_sdvo,
-                                  SDVO_CMD_GET_SUPPORTED_ENHANCEMENTS,
-                                  &enhancements, sizeof(enhancements)))
-                return false;
-
+        enhancements.response = 0;
+        intel_sdvo_get_value(intel_sdvo,
+                             SDVO_CMD_GET_SUPPORTED_ENHANCEMENTS,
+                             &enhancements, sizeof(enhancements));
         if (enhancements.response == 0) {
                 DRM_DEBUG_KMS("No enhancement is supported\n");
                 return true;