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@xxxxxxxxx Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> --- 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; -- 2.1.4 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
