On Mon, 6 Aug 2012, Daniel Vetter wrote: > On Mon, Aug 6, 2012 at 6:21 AM, Hugh Dickins <hu...@google.com> wrote: > > On Sun, 5 Aug 2012, Takashi Iwai wrote: > >> At Sat, 4 Aug 2012 10:01:13 -0700 (PDT), > >> Hugh Dickins wrote: > >> > > >> > Sorry to report that with 3.6-rc1, closing and opening the lid on > >> > this ThinkPad T420s leaves the screen blank, and I have to reboot. > >> > > >> > Bisection led to this commit, and reverting indeed gets my screen back: > >> > > >> > commit 520c41cf2fa029d1e8b923ac2026f96664f17c4b > >> > Author: Daniel Vetter <daniel.vet...@ffwll.ch> > >> > Date: Wed Jul 11 16:27:52 2012 +0200 > >> > > >> > drm/i915/lvds: ditch ->prepare special case > > ... > >> > >> Hm, it's surprising. > >> > >> Could you check whether the counter-part intel_lvds_enable() is > >> called? If the prepare callback affects, it must be from the mode > >> setting (drm_crtc_helper_set_mode()). > > > > Yes, I put a dump_stack() in both, and intel_lvds_enable() gets called > > about 0.28 seconds after the intel_lvds_disable() when I lift the lid; > > but with no video display until I revert that commit. > > Can you please boot with drm.debug=0xe added to your kernel cmdline, > reproduce the issue (with the two dump_stack calls added) and then > attach the full dmesg?
Collected, I'll send it to you both privately in a moment. > > Also a few other things to try: What happens if you do a modeset on > the LVDS while it's still working, e.g. In the dmesg, I've only gone to runlevel 3, simply working on the console without startx. For these xrandrs to work, I did startx and used the graphics screen. > > xrandr --outpu LVDS1 --auto --crtc 1 Blanks and restores the screen. > > then switch back to crtc 0 with > > xrandr --outpu LVDS1 --auto --crtc 0 Blanks and restores the screen. > > Would also be interesting to know whether this can resurrect your machine. Indeed it does: the first (--crtc 1) restores the display from its blank state after opening the lid, the second (--crtc 0) then behaves as before, briefly blanking then restoring the display. > > Also, how blank is the screen? I.e. is only the backlight off, but you > can (dimly) see some screen contents, or is it completely off? Completely off. Thanks, Hugh -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
