drm/i915/ddi: only call shutdown hooks for valid encoders

commit 60a43ecbd59decb77b31c09a73f09e1d4f4d1c4c upstream.

DDI might be HDMI or DP only, leaving the other encoder
uninitialized. Calling the shutdown hook on an uninitialized encoder may
lead to a NULL pointer dereference. Check the encoder types (and thus
validity via the DP output_reg or HDMI hdmi_reg checks) before calling
the hooks.

Reported-and-tested-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Closes: https://lore.kernel.org/r/20241031105145.2140590-1-senozhatsky@chromium.org
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Ville Syrjala <ville.syrjala@linux.intel.com>
Reviewed-by: Suraj Kandpal <suraj.kandpal@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/8b197c50e7f3be2bbc07e3935b21e919815015d5.1735568047.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
index 9e42f0836989e7a81e490a4708391371f4c85f6f..5b24460c01341749dbd866ea1f871cdd093a83eb 100644 (file)
--- a/drivers/gpu/drm/i915/display/intel_ddi.c
+++ b/drivers/gpu/drm/i915/display/intel_ddi.c
@@ -4798,8 +4798,10 @@ static void intel_ddi_tc_encoder_suspend_complete(struct intel_encoder *encoder)
 
 static void intel_ddi_encoder_shutdown(struct intel_encoder *encoder)
 {
-       intel_dp_encoder_shutdown(encoder);
-       intel_hdmi_encoder_shutdown(encoder);
+       if (intel_encoder_is_dp(encoder))
+               intel_dp_encoder_shutdown(encoder);
+       if (intel_encoder_is_hdmi(encoder))
+               intel_hdmi_encoder_shutdown(encoder);
 }
 
 static void intel_ddi_tc_encoder_shutdown_complete(struct intel_encoder *encoder)