From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jani Nikula Subject: Re: [Intel-gfx] [PATCH] drm/i915: Disable FBC on Haswell Date: Tue, 10 Jun 2014 19:44:39 +0300 Message-ID: <87wqcosoi0.fsf@intel.com> References: <1402047431-32737-1-git-send-email-chris@chris-wilson.co.uk> <87mwdmgdfh.fsf@intel.com> <20140609183630.GV27580@intel.com> <87k38phphm.fsf@intel.com> <20140610070643.GF5821@phenom.ffwll.local> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20140610070643.GF5821@phenom.ffwll.local> Sender: stable-owner@vger.kernel.org To: Daniel Vetter Cc: Ville =?utf-8?B?U3lyasOkbMOk?= , intel-gfx@lists.freedesktop.org, stable@vger.kernel.org List-Id: intel-gfx@lists.freedesktop.org On Tue, 10 Jun 2014, Daniel Vetter wrote: > On Mon, Jun 09, 2014 at 10:06:29PM +0300, Jani Nikula wrote: >> On Mon, 09 Jun 2014, Ville Syrj=C3=A4l=C3=A4 wrote: >> > On Mon, Jun 09, 2014 at 09:12:18PM +0300, Jani Nikula wrote: >> >> On Fri, 06 Jun 2014, Chris Wilson wrot= e: >> >> > It causes black screen on bootup and is approximately 100x slow= er than >> >> > running with FBC disabled, so the GPU runs at a high frequency = for much >> >> > longer - completely contrary to the power saving claims. It als= o still >> >> > has mutex deadlocks in multi-head scenarios, which can lead to = a >> >> > system/X lockup. These bugs were known before FBC was enabled b= y default >> >> > on Haswell and still have not been fixed. >> >> > >> >> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=3D79716 >> >> > Reported-and-tested-by: Jon Kristensen >> >> > Signed-off-by: Chris Wilson >> >> > Cc: stable@vger.kernel.org >> >> > --- >> >> > drivers/gpu/drm/i915/intel_pm.c | 3 +-- >> >> > 1 file changed, 1 insertion(+), 2 deletions(-) >> >> > >> >> > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/= i915/intel_pm.c >> >> > index e403010540a5..0b8a6010427e 100644 >> >> > --- a/drivers/gpu/drm/i915/intel_pm.c >> >> > +++ b/drivers/gpu/drm/i915/intel_pm.c >> >> > @@ -511,8 +511,7 @@ void intel_update_fbc(struct drm_device *de= v) >> >> > obj =3D intel_fb->obj; >> >> > adjusted_mode =3D &intel_crtc->config.adjusted_mode; >> >> > =20 >> >> > - if (i915.enable_fbc < 0 && >> >> > - INTEL_INFO(dev)->gen <=3D 7 && !IS_HASWELL(dev)) { >> >> > + if (i915.enable_fbc < 0) { >> >>=20 >> >> Not only does this disable FBC by default on Haswell but also on = all >> >> current and future platforms, including Broadwell. Shouldn't you = leave >> >> the INTEL_INFO(dev)->gen <=3D 7 part intact? >> > >> > The current FBC code is universally broken. >>=20 >> Well, then the commit message should reflect that! :p > > s/Haswell/Haswell+/ and it's correct ;-) Pushed to -fixes with a little more verbose change. Thanks for the patc= h and review. BR, Jani. > -Daniel > --=20 > Daniel Vetter > Software Engineer, Intel Corporation > +41 (0) 79 365 57 48 - http://blog.ffwll.ch --=20 Jani Nikula, Intel Open Source Technology Center