drm/tegra: hdmi: Setup audio only if configured

The audio configuration is only valid if the HDMI codec has been properly set up. Do not attempt to set up audio before that happens because it causes a division by zero. Note that this is only problematic on Tegra20 and Tegra30. Later chips implement the division instructions which return zero when dividing by zero and don't throw an exception. Fixes: db5adf4 ("drm/tegra: hdmi: Fix audio to work with any pixel clock rate") Reported-by: Marcel Ziswiler <[email protected]> Tested-by: Dmitry Osipenko <[email protected]> Signed-off-by: Thierry Reding <[email protected]>
chewitt · Apr 17, 2019 · 83f8bf4 · 83f8bf4
1 parent 8bbad1b
commit 83f8bf4
Showing 1 changed file with 9 additions and 3 deletions.
diff --git a/drivers/gpu/drm/tegra/hdmi.c b/drivers/gpu/drm/tegra/hdmi.c
@@ -1260,9 +1260,15 @@ static void tegra_hdmi_encoder_enable(struct drm_encoder *encoder)
 
 	hdmi->dvi = !tegra_output_is_hdmi(output);
 	if (!hdmi->dvi) {
-		err = tegra_hdmi_setup_audio(hdmi);
-		if (err < 0)
-			hdmi->dvi = true;
+		/*
+		 * Make sure that the audio format has been configured before
+		 * enabling audio, otherwise we may try to divide by zero.
+		*/
+		if (hdmi->format.sample_rate > 0) {
+			err = tegra_hdmi_setup_audio(hdmi);
+			if (err < 0)
+				hdmi->dvi = true;
+		}
 	}
 
 	if (hdmi->config->has_hda)