On Fri, Jun 19, 2015 at 01:57:43PM +0100, Chris Wilson wrote: > 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> Reviewed-by: Damien Lespiau <damien.lespiau@xxxxxxxxx> > --- > 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 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
