Merge tag 'drm-fixes-for-v4.17-rc2' of git://people.freedesktop.org/~airlied/linux

Pull drm fixes from Dave Airlie:
 "Exynos, i915, vc4, amdgpu fixes.

  i915:
   - an oops fix
   - two race fixes
   - some gvt fixes

  amdgpu:
   - dark screen fix
   - clk/voltage fix
   - vega12 smu fix

  vc4:
   - memory leak fix

  exynos just drops some code"

* tag 'drm-fixes-for-v4.17-rc2' of git://people.freedesktop.org/~airlied/linux: (23 commits)
  drm/amd/powerplay: header file interface to SMU update
  drm/amd/pp: Fix bug voltage can't be OD separately on VI
  drm/amd/display: Don't program bypass on linear regamma LUT
  drm/i915: Fix LSPCON TMDS output buffer enabling from low-power state
  drm/i915/audio: Fix audio detection issue on GLK
  drm/i915: Call i915_perf_fini() on init_hw error unwind
  drm/i915/bios: filter out invalid DDC pins from VBT child devices
  drm/i915/pmu: Inspect runtime PM state more carefully while estimating RC6
  drm/i915: Do no use kfree() to free a kmem_cache_alloc() return value
  drm/exynos: exynos_drm_fb -> drm_framebuffer
  drm/exynos: Move dma_addr out of exynos_drm_fb
  drm/exynos: Move GEM BOs to drm_framebuffer
  drm: Fix HDCP downstream dev count read
  drm/vc4: Fix memory leak during BO teardown
  drm/i915/execlists: Clear user-active flag on preemption completion
  drm/i915/gvt: Add drm_format_mod update
  drm/i915/gvt: Disable primary/sprite/cursor plane at virtual display initialization
  drm/i915/gvt: Delete redundant error message in fb_decode.c
  drm/i915/gvt: Cancel dma map when resetting ggtt entries
  drm/i915/gvt: Missed to cancel dma map for ggtt entries
  ...

1 files changed, 32 insertions, 7 deletions

diff --git a/drivers/gpu/drm/drm_dp_dual_mode_helper.c b/drivers/gpu/drm/drm_dp_dual_mode_helper.c
index 02a5092..e7f4fe2 100644
--- a/drivers/gpu/drm/drm_dp_dual_mode_helper.c
+++ b/drivers/gpu/drm/drm_dp_dual_mode_helper.c
@@ -350,19 +350,44 @@ int drm_dp_dual_mode_set_tmds_output(enum drm_dp_dual_mode_type type,
 {
 	uint8_t tmds_oen = enable ? 0 : DP_DUAL_MODE_TMDS_DISABLE;
 	ssize_t ret;
+	int retry;
 
 	if (type < DRM_DP_DUAL_MODE_TYPE2_DVI)
 		return 0;
 
-	ret = drm_dp_dual_mode_write(adapter, DP_DUAL_MODE_TMDS_OEN,
-				     &tmds_oen, sizeof(tmds_oen));
-	if (ret) {
-		DRM_DEBUG_KMS("Failed to %s TMDS output buffers\n",
-			      enable ? "enable" : "disable");
-		return ret;
+	/*
+	 * LSPCON adapters in low-power state may ignore the first write, so
+	 * read back and verify the written value a few times.
+	 */
+	for (retry = 0; retry < 3; retry++) {
+		uint8_t tmp;
+
+		ret = drm_dp_dual_mode_write(adapter, DP_DUAL_MODE_TMDS_OEN,
+					     &tmds_oen, sizeof(tmds_oen));
+		if (ret) {
+			DRM_DEBUG_KMS("Failed to %s TMDS output buffers (%d attempts)\n",
+				      enable ? "enable" : "disable",
+				      retry + 1);
+			return ret;
+		}
+
+		ret = drm_dp_dual_mode_read(adapter, DP_DUAL_MODE_TMDS_OEN,
+					    &tmp, sizeof(tmp));
+		if (ret) {
+			DRM_DEBUG_KMS("I2C read failed during TMDS output buffer %s (%d attempts)\n",
+				      enable ? "enabling" : "disabling",
+				      retry + 1);
+			return ret;
+		}
+
+		if (tmp == tmds_oen)
+			return 0;
 	}
 
-	return 0;
+	DRM_DEBUG_KMS("I2C write value mismatch during TMDS output buffer %s\n",
+		      enable ? "enabling" : "disabling");
+
+	return -EIO;
 }
 EXPORT_SYMBOL(drm_dp_dual_mode_set_tmds_output);