From 043029655816ed4cfc2ed247020ef97e5d637392 Mon Sep 17 00:00:00 2001 From: Shaohua Li Date: Mon, 24 Aug 2009 10:25:23 +0800 Subject: drm/i915: Support IGD EOS In the event that any one of the DAC analog outputs (R,G,B) were driven at full-scale (white video) or some analog level close to full-scale voltage, and if the video cable were then disconnected, the analog video voltage level would exceed the maximum electrical overstress limit of the native (thin-oxide) transistors thus causing a long-term reliability concern. The electrical overstress condition occurs in this particular case. This patch address the IGD EOS (electrical overstress condition) issue. When the EOS interrupt occurs, OS should disable DAC and then disable EOS, then the normal hotplug operation follows. TODO: it appears the normal unplug interrupt is missed as reported by Li Peng, need more checks here. Signed-off-by: Shaohua Li Signed-off-by: Eric Anholt --- drivers/gpu/drm/i915/intel_crt.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'drivers/gpu/drm/i915/intel_crt.c') diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c index 590f81c8f594..88814fa2dfd2 100644 --- a/drivers/gpu/drm/i915/intel_crt.c +++ b/drivers/gpu/drm/i915/intel_crt.c @@ -64,6 +64,34 @@ static void intel_crt_dpms(struct drm_encoder *encoder, int mode) } I915_WRITE(reg, temp); + + if (IS_IGD(dev)) { + if (mode == DRM_MODE_DPMS_OFF) { + /* turn off DAC */ + temp = I915_READ(PORT_HOTPLUG_EN); + temp &= ~CRT_EOS_INT_EN; + I915_WRITE(PORT_HOTPLUG_EN, temp); + + temp = I915_READ(PORT_HOTPLUG_STAT); + if (temp & CRT_EOS_INT_STATUS) + I915_WRITE(PORT_HOTPLUG_STAT, + CRT_EOS_INT_STATUS); + } else { + /* turn on DAC. EOS interrupt must be enabled after DAC + * is enabled, so it sounds not good to enable it in + * i915_driver_irq_postinstall() + * wait 12.5ms after DAC is enabled + */ + msleep(13); + temp = I915_READ(PORT_HOTPLUG_STAT); + if (temp & CRT_EOS_INT_STATUS) + I915_WRITE(PORT_HOTPLUG_STAT, + CRT_EOS_INT_STATUS); + temp = I915_READ(PORT_HOTPLUG_EN); + temp |= CRT_EOS_INT_EN; + I915_WRITE(PORT_HOTPLUG_EN, temp); + } + } } static int intel_crt_mode_valid(struct drm_connector *connector, -- cgit v1.2.1