We have one bug report from a validation team that we get the eDP panel sequencing still somewhat wrong: We need to enable VDD while switching off the panel and backlight. Unfortunately that reporter seems to have fallen off the earth :( For another reporter this actually fixes a black panel issue because without this the backlight/panel gets confused and doesn't light up again. v2: I've forgotten to remove the vdd_off call in panel_off which is now bogus. This essentially reverts commit 17038de5f16569a25343cf68668f3b657eafb00e Author: Chris Wilson <chris at chris-wilson.co.uk> Date: Mon Apr 16 22:43:42 2012 +0100 drm/i915/dp: Flush any outstanding work to turn the VDD off v3: the current panel_off code forces off the vdd power, too. Which is bogus and resulted in some funny warnings later on when we've tried to do aux channel communications with just the vdd forced on. Fix this, too. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=46312 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=43163 Tested-by: Vincent Frentzel <zcecc22 at gmail.com> Cc: stable at kernel.org Signed-Off-by: Daniel Vetter <daniel.vetter at ffwll.ch> --- drivers/gpu/drm/i915/intel_dp.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index a1a5ce7..3bbd754 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -1154,11 +1154,10 @@ static void ironlake_edp_panel_off(struct intel_dp *intel_dp) DRM_DEBUG_KMS("Turn eDP power off\n"); - WARN(intel_dp->want_panel_vdd, "Cannot turn power off while VDD is on\n"); - ironlake_panel_vdd_off_sync(intel_dp); /* finish any pending work */ + WARN(!intel_dp->want_panel_vdd, "Need VDD to turn off panel\n"); pp = ironlake_get_pp_control(dev_priv); - pp &= ~(POWER_TARGET_ON | EDP_FORCE_VDD | PANEL_POWER_RESET | EDP_BLC_ENABLE); + pp &= ~(POWER_TARGET_ON | PANEL_POWER_RESET | EDP_BLC_ENABLE); I915_WRITE(PCH_PP_CONTROL, pp); POSTING_READ(PCH_PP_CONTROL); @@ -1266,18 +1265,16 @@ static void intel_dp_prepare(struct drm_encoder *encoder) { struct intel_dp *intel_dp = enc_to_intel_dp(encoder); + + /* Make sure the panel is off before trying to change the mode. But also + * ensure that we have vdd while we switch off the panel. */ + ironlake_edp_panel_vdd_on(intel_dp); ironlake_edp_backlight_off(intel_dp); ironlake_edp_panel_off(intel_dp); - /* Wake up the sink first */ - ironlake_edp_panel_vdd_on(intel_dp); intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_ON); intel_dp_link_down(intel_dp); ironlake_edp_panel_vdd_off(intel_dp, false); - - /* Make sure the panel is off before trying to - * change the mode - */ } static void intel_dp_commit(struct drm_encoder *encoder) @@ -1309,10 +1306,11 @@ intel_dp_dpms(struct drm_encoder *encoder, int mode) uint32_t dp_reg = I915_READ(intel_dp->output_reg); if (mode != DRM_MODE_DPMS_ON) { + /* Switching the panel off requires vdd. */ + ironlake_edp_panel_vdd_on(intel_dp); ironlake_edp_backlight_off(intel_dp); ironlake_edp_panel_off(intel_dp); - ironlake_edp_panel_vdd_on(intel_dp); intel_dp_sink_dpms(intel_dp, mode); intel_dp_link_down(intel_dp); ironlake_edp_panel_vdd_off(intel_dp, false); -- 1.7.10