Testing with NetBSD 7.0_BETA (GENERIC.201503202050Z) on a Westmere/Ironlake (Intel HD Graphics), the screen goes blank during boot and also stays that way, when starting X (after logging in blindly). Maybe you can get an idea from these error messages:
agp0 at pchb0: G4X-family chipset agp0: detected 32252k stolen memory agp0: aperture at 0x80000000, size 0x10000000 i915drmkms0 at pci0 dev 2 function 0: vendor 0x8086 product 0x0046 (rev. 0x02) drm: Memory usable by graphics device = 512M drm: Supports vblank timestamp caching Rev 2 (21.10.2013). drm: Driver supports precise vblank timestamp query. i915drmkms0: interrupting at ioapic0 pin 16 (i915) intelfb0 at i915drmkms0 i915drmkms0: info: registered panic notifier intelfb0: framebuffer at 0xffff800022aa2000, size 1920x1080, depth 32, stride 7680 DRM error in intel_dp_start_link_train: failed to enable link training DRM error in intel_dp_complete_link_train: failed to train DP, aborting warning: /usr/src/sys/external/bsd/drm2/dist/drm/i915/intel_display.c:9818: encoder's hw state doesn't match sw tracking (expected 1, found 0) DRM error in intel_pipe_config_compare: mismatch in has_dp_encoder (expected 1, found 0) warning: /usr/src/sys/external/bsd/drm2/dist/drm/i915/intel_display.c:9891: pipe state doesn't match! wsdisplay0 at intelfb0 kbdmux 1: console (default, vt100 emulation), using wskbd0 wsmux1: connecting to wsdisplay0 intelfb0: failed to register shutdown handler I already filed a PR: kern/49768. Please let me know, if I can help debugging this issue.
