From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga05.intel.com ([192.55.52.43]:64200 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726938AbeIZTxl (ORCPT ); Wed, 26 Sep 2018 15:53:41 -0400 Date: Wed, 26 Sep 2018 06:40:20 -0700 From: Rodrigo Vivi To: Mika Kuoppala Cc: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= , intel-gfx@lists.freedesktop.org, Paulo Zanoni , Chris Wilson , stable@vger.kernel.org Subject: Re: [PATCH] drm/i915/fbc: Disable fbc with VT-d also with kbl and cfl Message-ID: <20180926134020.GF2262@intel.com> References: <20180925133803.23677-1-mika.kuoppala@linux.intel.com> <20180925151552.GJ9144@intel.com> <87va6sl8mw.fsf@gaia.fi.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87va6sl8mw.fsf@gaia.fi.intel.com> Sender: stable-owner@vger.kernel.org List-ID: On Wed, Sep 26, 2018 at 03:56:39PM +0300, Mika Kuoppala wrote: > Ville Syrj�l� writes: > > > On Tue, Sep 25, 2018 at 04:38:03PM +0300, Mika Kuoppala wrote: > >> Using fbc with VT-d flickers also on kbl and cfl. > >> > >> Cc: Paulo Zanoni > >> Cc: Ville Syrj�l� > >> Cc: Chris Wilson > >> Cc: Rodrigo Vivi > >> Cc: # v4.9+ > >> Signed-off-by: Mika Kuoppala > >> --- > >> drivers/gpu/drm/i915/intel_fbc.c | 5 +++-- > >> 1 file changed, 3 insertions(+), 2 deletions(-) > >> > >> diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c > >> index 74d425c700ef..a149f08c1b79 100644 > >> --- a/drivers/gpu/drm/i915/intel_fbc.c > >> +++ b/drivers/gpu/drm/i915/intel_fbc.c > >> @@ -1275,9 +1275,10 @@ static int intel_sanitize_fbc_option(struct drm_i915_private *dev_priv) > >> > >> static bool need_fbc_vtd_wa(struct drm_i915_private *dev_priv) > >> { > >> - /* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl,bxt */ > >> + /* WaFbcTurnOffFbcWhenHyperVisorIsUsed:skl,bxt,kbl,cfl */ > > > > The hsds seem to be saying that this was fixed in kbl/cnl. I guess the > > flicker could be due to a different vt-d vs. fbc issue. > > > > I was trusting the wa database on this one. I believe it would be worth to trust the wa_database, but this database can be tricky too... Like on this case it is listed for KBL, but A0 only and not listed for CFL. > > > Is the chicken bit in CHICKEN_PIPESL in the correct position? > > Yes it is zero. > > > > > Hmm. Bspec doesn't list chicken bit for glk. That would seem to suggest > > that we need this w/a for glk as well. > > Agreed. The questio is that should we follow bspec and logic or > leave it until we get a report if it is a problem? > > cfl is close enough|similar in this respect that we mimic > kbl with it? yes, we can safely consider it is similar to latest steppings of KBL. > > Thanks, > -Mika > > > > >> if (intel_vtd_active() && > >> - (IS_SKYLAKE(dev_priv) || IS_BROXTON(dev_priv))) { > >> + (IS_SKYLAKE(dev_priv) || IS_BROXTON(dev_priv) || > >> + IS_KABYLAKE(dev_priv) || IS_COFFEELAKE(dev_priv))) { > >> DRM_INFO("Disabling framebuffer compression (FBC) to prevent screen flicker with VT-d enabled\n"); > >> return true; > >> } > >> -- > >> 2.17.1 > > > > -- > > Ville Syrj�l� > > Intel