[PATCH] drm/exynos: hdmi: fix power order issue

[Inki Dae]

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.

Signed-off-by: Inki Dae <inki.dae at samsung.com>
---
 drivers/gpu/drm/exynos/exynos_hdmi.c |   19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/drivers/gpu/drm/exynos/exynos_hdmi.c 
b/drivers/gpu/drm/exynos/exynos_hdmi.c
index c104d0c..aa259b0 100644
--- a/drivers/gpu/drm/exynos/exynos_hdmi.c
+++ b/drivers/gpu/drm/exynos/exynos_hdmi.c
@@ -2090,6 +2090,11 @@ 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) {
@@ -2099,6 +2104,20 @@ 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:
-- 
1.7.9.5