From 72c3500ac4c260df661906dd6da484b35d149985 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Mon, 18 Aug 2014 22:16:00 +0300 Subject: [PATCH] drm/i915: Add a note explaining vdd on/off handling in intel_dp_aux_ch() MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Add a comment to explain why we care about the current want_panel_vdd state in intel_dp_aux_ch(). Signed-off-by: Ville Syrjälä Reviewed-by: Jani Nikula Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_dp.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index 190e617f128e..a45069b6c7e5 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -533,6 +533,12 @@ intel_dp_aux_ch(struct intel_dp *intel_dp, bool has_aux_irq = HAS_AUX_IRQ(dev); bool vdd; + /* + * We will be called with VDD already enabled for dpcd/edid/oui reads. + * In such cases we want to leave VDD enabled and it's up to upper layers + * to turn it off. But for eg. i2c-dev access we need to turn it on/off + * ourselves. + */ vdd = edp_panel_vdd_on(intel_dp); /* dp aux is extremely sensitive to irq latency, hence request the -- 2.20.1