Merge tag 'drm/tegra/for-5.1-rc6' of git://anongit.freedesktop.org/tegra/linux into drm-fixes

drm/tegra: Fixes for v5.1-rc6

This contains a follow-up fix for the stream ID programming and a fix
for a regression on older Tegra devices (Tegra20 and Tegra30) that are
running into a division by zero trying to enable audio over HDMI.
Signed-off-by: Dave Airlie <airlied@redhat.com>

From: Thierry Reding <thierry.reding@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190417073525.21680-1-thierry.reding@gmail.com

drivers/gpu/drm/tegra/hdmi.c

@@ -1260,10 +1260,16 @@ static void tegra_hdmi_encoder_enable(struct drm_encoder *encoder)
 
 	hdmi->dvi = !tegra_output_is_hdmi(output);
 	if (!hdmi->dvi) {
+		/*
+		 * 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)
 		tegra_hdmi_write_eld(hdmi);

drivers/gpu/host1x/hw/channel_hw.c

@@ -114,9 +114,13 @@ static inline void synchronize_syncpt_base(struct host1x_job *job)
 
 static void host1x_channel_set_streamid(struct host1x_channel *channel)
 {
-#if IS_ENABLED(CONFIG_IOMMU_API) &&  HOST1X_HW >= 6
+#if HOST1X_HW >= 6
+	u32 sid = 0x7f;
+#ifdef CONFIG_IOMMU_API
 	struct iommu_fwspec *spec = dev_iommu_fwspec_get(channel->dev->parent);
-	u32 sid = spec ? spec->ids[0] & 0xffff : 0x7f;
+	if (spec)
+		sid = spec->ids[0] & 0xffff;
+#endif
 
 	host1x_ch_writel(channel, sid, HOST1X_CHANNEL_SMMU_STREAMID);
 #endif