Re: HEADS UP: graphics driver fixes

[Joachim Henke <free.software%gmx.com@localhost>]

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.