Re: kern/49398 (i386-current GENERIC (i915drmkms) boot hangs if monitor powered off)

["John D. Baker" <jdbaker%mylinuxisp.com@localhost>]

The following reply was made to PR kern/49398; it has been noted by GNATS.

From: "John D. Baker" <jdbaker%mylinuxisp.com@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: kern/49398 (i386-current GENERIC (i915drmkms) boot hangs if
 monitor powered off)
Date: Tue, 20 Oct 2015 15:36:20 -0500 (CDT)

 On Thu, 14 May 2015, riastradh%NetBSD.org@localhost wrote:
 
 > If not, we can try printf debugging.  I'd start by adding printfs
 > around all the calls to drm_add_edid_modes in i915, and throughout
 > drmfb_attach.  That should be enough to get started, but I can supply
 > a patch if you'd like.
 
 OK, I've done this.  I booted with video connected and powered on to get
 a reference of where the output appears:
 
 [...]
 pchb0 at pci0 dev 0 function 0: Intel 82845G/GL DRAM Controller / Host-Hub I/F B
 ridge (rev. 0x01)
 agp0 at pchb0: i830-family chipset
 agp0: detected 8060k stolen memory
 agp0: aperture at 0xf0000000, size 0x8000000
 i915drmkms0 at pci0 dev 2 function 0: Intel 82845G/GL Integrated Graphics Device
  (rev. 0x01)
 drm: Memory usable by graphics device = 128M
 drm: Supports vblank timestamp caching Rev 2 (21.10.2013).
 drm: Driver supports precise vblank timestamp query.
 i915drmkms0: interrupting at ioapic0 pin 16 (i915)
 drm: initialized overlay support
 In /x/nbsd-tst/src/sys/external/bsd/drm2/dist/drm/i915/intel_modes.c: line 45
 In /x/nbsd-tst/src/sys/external/bsd/drm2/dist/drm/i915/intel_modes.c: line 47
 intelfb0 at i915drmkms0
 i915drmkms0: info: registered panic notifier
 In /x/nbsd-tst/src/sys/external/bsd/drm2/drm/drmfb.c: line 96
 In /x/nbsd-tst/src/sys/external/bsd/drm2/drm/drmfb.c: line 117
 In /x/nbsd-tst/src/sys/external/bsd/drm2/drm/drmfb.c: line 136
 In /x/nbsd-tst/src/sys/external/bsd/drm2/drm/drmfb.c: line 145
 intelfb0: framebuffer at 0xdabd9000, size 1280x1024, depth 32, stride 5120
 wsdisplay0 at intelfb0 kbdmux 1: console (default, vt100 emulation), using wskbd
 0
 wsmux1: connecting to wsdisplay0
 In /x/nbsd-tst/src/sys/external/bsd/drm2/drm/drmfb.c: line 153
 [...]
 
 A subsequent boot with video disconnected shows the machine hangs before
 the first debug output line.
 
 [...]
 pchb0 at pci0 dev 0 function 0: Intel 82845G/GL DRAM Controller / Host-Hub I/F B
 ridge (rev. 0x01)
 agp0 at pchb0: i830-family chipset
 agp0: detected 8060k stolen memory
 agp0: aperture at 0xf0000000, size 0x8000000
 i915drmkms0 at pci0 dev 2 function 0: Intel 82845G/GL Integrated Graphics Device
  (rev. 0x01)
 drm: Memory usable by graphics device = 128M
 drm: Supports vblank timestamp caching Rev 2 (21.10.2013).
 drm: Driver supports precise vblank timestamp query.
 i915drmkms0: interrupting at ioapic0 pin 16 (i915)
 drm: initialized overlay support
 [hung]
 
 So, the hang occurs somewhere before the first call to
 "drm_add_edid_modes()".  I'll add printfs around where the "initialized
 overlay support" line is printed, etc.
 
 -- 
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