From eebaed646ab263cabcd19485e606e51c0bb11c5c Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Fri, 19 Jun 2015 13:57:43 +0100 Subject: [PATCH] drm/i915: Ignore LVDS presence in VBT flag if the LVDS is enabled by BIOS On older gen, pre-Ironlake, parts there is no hardwired pin to report the presence of an LVDS panel. Instead, we have to rely on the VBT to declare whether the machine has a panel or not. Though notoriously unreliable, so far we have erred on the side of false-positives and have required a list of machines which end up falsely reporting a panel as present. However, we now have reports of false-negatives, machines with an LVDS that are being ignored due to the VBT not declaring the panel. This patch ignores the VBT setting if the BIOS has already enabled the LVDS panel (and on Ironlake+ we also have the hardware presence pin). It fixes the Samsung NP680Z5E-X01FR in the bug report, but is likely to result in more false-positives, and since we rely on the BIOS to enable the panel, there are likely different circumstances where the BIOS will not enable that panel (and so we may see the same machine with and without a panel all on the whim of the BIOS). Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=90979 Reported-and-tested-by: lysxia@gmail.com Signed-off-by: Chris Wilson Reviewed-by: Damien Lespiau Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_lvds.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c index 161ab26f81fb..bf1702a6e33d 100644 --- a/drivers/gpu/drm/i915/intel_lvds.c +++ b/drivers/gpu/drm/i915/intel_lvds.c @@ -942,12 +942,6 @@ void intel_lvds_init(struct drm_device *dev) if (dmi_check_system(intel_no_lvds)) return; - pin = GMBUS_PIN_PANEL; - if (!lvds_is_present_in_vbt(dev, &pin)) { - DRM_DEBUG_KMS("LVDS is not present in VBT\n"); - return; - } - if (HAS_PCH_SPLIT(dev)) { if ((I915_READ(PCH_LVDS) & LVDS_DETECTED) == 0) return; @@ -957,6 +951,16 @@ void intel_lvds_init(struct drm_device *dev) } } + pin = GMBUS_PIN_PANEL; + if (!lvds_is_present_in_vbt(dev, &pin)) { + u32 reg = HAS_PCH_SPLIT(dev) ? PCH_LVDS : LVDS; + if ((I915_READ(reg) & LVDS_PORT_EN) == 0) { + DRM_DEBUG_KMS("LVDS is not present in VBT\n"); + return; + } + DRM_DEBUG_KMS("LVDS is not present in VBT, but enabled anyway\n"); + } + lvds_encoder = kzalloc(sizeof(*lvds_encoder), GFP_KERNEL); if (!lvds_encoder) return; -- 2.20.1