Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760005Ab2HJSym (ORCPT ); Fri, 10 Aug 2012 14:54:42 -0400 Received: from mail-yw0-f46.google.com ([209.85.213.46]:50412 "EHLO mail-yw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754697Ab2HJSyk (ORCPT ); Fri, 10 Aug 2012 14:54:40 -0400 Date: Fri, 10 Aug 2012 11:53:51 -0700 (PDT) From: Hugh Dickins X-X-Sender: hugh@eggly.anvils To: Takashi Iwai cc: Daniel Vetter , Linus Torvalds , Chris Wilson , Giacomo Comes , Paulo Zanoni , linux-kernel@vger.kernel.org Subject: Re: i915 regression on 3.6-rc1: lid blanks screen In-Reply-To: Message-ID: References: User-Agent: Alpine 2.00 (LSU 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7182 Lines: 184 On Fri, 10 Aug 2012, Takashi Iwai wrote: > At Fri, 10 Aug 2012 14:35:13 +0200, > Daniel Vetter wrote: > > > > On Fri, Aug 10, 2012 at 1:59 PM, Takashi Iwai wrote: > > > At Mon, 6 Aug 2012 11:25:30 -0700 (PDT), > > > Hugh Dickins wrote: > > >> > > >> On Mon, 6 Aug 2012, Daniel Vetter wrote: > > >> > On Mon, Aug 6, 2012 at 6:21 AM, Hugh Dickins 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 > > >> > >> > 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. > > > > > > OK, now I can see the problem here, too. The key is that it happens > > > only on Linux console, not on X. That's why no one else reported. > > > I guess the problem can be seen on many laptops with LVDS on PCH. A correction there: for me it was happening both on X and on console; but once I found that it happened even on the simple console, I mostly stuck to bisecting and testing on that. > > > > > > Looking at intel_reg_dumper output, BLC_PWM_CPU_CTL is 0 while other > > > registers are set correctly. This seems coming from the rewrite of > > > backlight control code by commit > > > 24ded204: drm/i915: properly enable the blc controller on the right pipe > > > and > > > a4f32fc3: drm/i915: don't forget the PCH backlight registers > > > > > > While the latter fixes the regression by the former commit, it still > > > doesn't cover this regression. > > > > > > I don't know the exact hardware behavior, but it looks like that > > > resetting BLC_PWM_PCH_CTL2 and BLC_PWM_PCH_CTL1 clears the > > > BLC_PWM_CPU_CTL (oh what confusing reg names). > > > > > > FWIW, the commit 520c41cf you mentioned is no direct cause. This > > > patch works fine on the top of 3.5 kernel. But it's like a bad drug, > > > the combination of this and other two commits break things. > > > > > > The patch below is my quick fix. It worked on an HP laptop. > > > Hugh, could you give it a try? > > > > Hm, this sounds eerily familiar to the backlight bug you've recently fixed in > > > > commit 6db65cbb941f9d433659bdad02b307f6d94465df > > Author: Takashi Iwai > > Date: Thu Jun 21 15:30:41 2012 +0200 > > > > drm/i915: Fix eDP blank screen after S3 resume on HP desktops > > > > Have you checked other code-paths for such issues? > > Not yet, I'd leave such a joy rather to you guys :) > > > The resume code > > seems to follow this order already ... also, when you submit this > > patch, can you please add a small comment to explain the ordering > > constraint, like in the resume register restore function? > > Sure, I'll add a comment and resubmit once when I hear it really fixes > on Hugh's machine, too. Indeed, your patch really fixes it on my machine: many thanks! Hugh > > > thanks, > > Takashi > > > > > Thanks, Daniel > > > > > > > > > > > thanks, > > > > > > Takashi > > > > > > === > > > From: Takashi Iwai > > > Subject: [PATCH] drm/i915: Fix blank panel at reopening lid on Linux console > > > > > > When you reopen the lid on Linux console on a laptop with PCH, the > > > panel suddenly goes blank. It seems because BLC_PWM_CPU_CTL register > > > is cleared when BLC_PWM_PCH_CTL1 and BLC_PWM_PCH_CTL2 registers are > > > played. > > > > > > This patch fixes the problem by setting BLC_PWM_CPU_CTL after enabling > > > BLC_PWM_PCH_CTL_1 and _2 registers. > > > > > > Signed-off-by: Takashi Iwai > > > --- > > > drivers/gpu/drm/i915/intel_panel.c | 9 +++++---- > > > 1 file changed, 5 insertions(+), 4 deletions(-) > > > > > > diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c > > > index 10c7d39..d640425 100644 > > > --- a/drivers/gpu/drm/i915/intel_panel.c > > > +++ b/drivers/gpu/drm/i915/intel_panel.c > > > @@ -311,9 +311,6 @@ void intel_panel_enable_backlight(struct drm_device *dev, > > > if (dev_priv->backlight_level == 0) > > > dev_priv->backlight_level = intel_panel_get_max_backlight(dev); > > > > > > - dev_priv->backlight_enabled = true; > > > - intel_panel_actually_set_backlight(dev, dev_priv->backlight_level); > > > - > > > if (INTEL_INFO(dev)->gen >= 4) { > > > uint32_t reg, tmp; > > > > > > @@ -326,7 +323,7 @@ void intel_panel_enable_backlight(struct drm_device *dev, > > > * we don't track the backlight dpms state, hence check whether > > > * we have to do anything first. */ > > > if (tmp & BLM_PWM_ENABLE) > > > - return; > > > + goto set_level; > > > > > > if (dev_priv->num_pipe == 3) > > > tmp &= ~BLM_PIPE_SELECT_IVB; > > > @@ -347,6 +344,10 @@ void intel_panel_enable_backlight(struct drm_device *dev, > > > I915_WRITE(BLC_PWM_PCH_CTL1, tmp); > > > } > > > } > > > + > > > +set_level: > > > + dev_priv->backlight_enabled = true; > > > + intel_panel_actually_set_backlight(dev, dev_priv->backlight_level); > > > } > > > > > > static void intel_panel_init_backlight(struct drm_device *dev) > > > -- > > > 1.7.11.4 > > > > > > > > > > > -- > > Daniel Vetter > > daniel.vetter@ffwll.ch - +41 (0) 79 365 57 48 - http://blog.ffwll.ch -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/