drm/exynos: hdmi: fix power order issue

This patch resolves page fault issue of Mixer when disabled.

The SFRs of VP and Mixer are updated by Vertical Sync of Timing
generator which is a part of HDMI so the sequence to disable TV
Subsystem should be as following:
	VP -> Mixer -> HDMI

For this, this patch disables Mixer and VP (if used) prior to
disabling HDMI.

Change-Id: I85591e66264c9e5b7efe7ddf7fe71df1b9972356
Signed-off-by: Inki Dae <inki.dae@samsung.com>

diff --git a/drivers/gpu/drm/exynos/exynos_hdmi.c b/drivers/gpu/drm/exynos/exynos_hdmi.c
index 337e4d6..eabf38b 100644 (file)
--- a/drivers/gpu/drm/exynos/exynos_hdmi.c
+++ b/drivers/gpu/drm/exynos/exynos_hdmi.c
@@ -1903,6 +1903,11 @@ out:
 
 static void hdmi_dpms(struct exynos_drm_display *display, int mode)
 {
+       struct hdmi_context *hdata = display->ctx;
+       struct drm_encoder *encoder = hdata->encoder;
+       struct drm_crtc *crtc = encoder->crtc;
+       struct drm_crtc_helper_funcs *funcs = NULL;
+
        DRM_DEBUG_KMS("mode %d\n", mode);
 
        switch (mode) {
@@ -1912,6 +1917,20 @@ static void hdmi_dpms(struct exynos_drm_display *display, int mode)
        case DRM_MODE_DPMS_STANDBY:
        case DRM_MODE_DPMS_SUSPEND:
        case DRM_MODE_DPMS_OFF:
+               /*
+                * The SFRs of VP and Mixer are updated by Vertical Sync of
+                * Timing generator which is a part of HDMI so the sequence
+                * to disable TV Subsystem should be as following,
+                *      VP -> Mixer -> HDMI
+                *
+                * Below codes will try to disable Mixer and VP(if used)
+                * prior to disabling HDMI.
+                */
+               if (crtc)
+                       funcs = crtc->helper_private;
+               if (funcs && funcs->dpms)
+                       (*funcs->dpms)(crtc, mode);
+
                hdmi_poweroff(display);
                break;
        default: