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30 Apr 2020 04:22:02 -0700 Received: by stinkbox (sSMTP sendmail emulation); Thu, 30 Apr 2020 14:22:02 +0300 Date: Thu, 30 Apr 2020 14:22:02 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: "Lisovskiy, Stanislav" Message-ID: <20200430112202.GU6112@intel.com> References: <20200423075902.21892-1-stanislav.lisovskiy@intel.com> <20200423075902.21892-4-stanislav.lisovskiy@intel.com> <20200430092104.GO6112@intel.com> <20200430100515.GA2691@intel.com> <20200430103217.GR6112@intel.com> <20200430104702.GA31341@intel.com> <20200430105559.GT6112@intel.com> <20200430110702.GA22144@intel.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200430110702.GA22144@intel.com> X-Patchwork-Hint: comment User-Agent: Mutt/1.10.1 (2018-07-13) Subject: Re: [Intel-gfx] [PATCH v26 3/9] drm/i915: Track active_pipes in bw_state X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: intel-gfx@lists.freedesktop.org Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Thu, Apr 30, 2020 at 02:07:02PM +0300, Lisovskiy, Stanislav wrote: > On Thu, Apr 30, 2020 at 01:55:59PM +0300, Ville Syrj=E4l=E4 wrote: > > On Thu, Apr 30, 2020 at 01:47:02PM +0300, Lisovskiy, Stanislav wrote: > > > On Thu, Apr 30, 2020 at 01:32:17PM +0300, Ville Syrj=E4l=E4 wrote: > > > > On Thu, Apr 30, 2020 at 01:05:15PM +0300, Lisovskiy, Stanislav wrot= e: > > > > > On Thu, Apr 30, 2020 at 12:21:04PM +0300, Ville Syrj=E4l=E4 wrote: > > > > > > On Thu, Apr 23, 2020 at 10:58:56AM +0300, Stanislav Lisovskiy w= rote: > > > > > > > We need to calculate SAGV mask also in a non-modeset > > > > > > > commit, however currently active_pipes are only calculated > > > > > > > for modesets in global atomic state, thus now we will be > > > > > > > tracking those also in bw_state in order to be able to > > > > > > > properly access global data. > > > > > > > = > > > > > > > Signed-off-by: Stanislav Lisovskiy > > > > > > > --- > > > > > > > drivers/gpu/drm/i915/display/intel_bw.h | 3 +++ > > > > > > > drivers/gpu/drm/i915/intel_pm.c | 15 ++++++++++----- > > > > > > > 2 files changed, 13 insertions(+), 5 deletions(-) > > > > > > > = > > > > > > > diff --git a/drivers/gpu/drm/i915/display/intel_bw.h b/driver= s/gpu/drm/i915/display/intel_bw.h > > > > > > > index d6df91058223..898b4a85ccab 100644 > > > > > > > --- a/drivers/gpu/drm/i915/display/intel_bw.h > > > > > > > +++ b/drivers/gpu/drm/i915/display/intel_bw.h > > > > > > > @@ -26,6 +26,9 @@ struct intel_bw_state { > > > > > > > = > > > > > > > unsigned int data_rate[I915_MAX_PIPES]; > > > > > > > u8 num_active_planes[I915_MAX_PIPES]; > > > > > > > + > > > > > > > + /* bitmask of active pipes */ > > > > > > > + u8 active_pipes; > > > > > > > }; > > > > > > > = > > > > > > > #define to_intel_bw_state(x) container_of((x), struct intel_= bw_state, base) > > > > > > > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/dr= m/i915/intel_pm.c > > > > > > > index 7e15cf3368ad..f7249bca3f6f 100644 > > > > > > > --- a/drivers/gpu/drm/i915/intel_pm.c > > > > > > > +++ b/drivers/gpu/drm/i915/intel_pm.c > > > > > > > @@ -3874,6 +3874,7 @@ static int intel_compute_sagv_mask(stru= ct intel_atomic_state *state) > > > > > > > struct intel_bw_state *new_bw_state =3D NULL; > > > > > > > const struct intel_bw_state *old_bw_state =3D NULL; > > > > > > > int i; > > > > > > > + bool active_pipes_calculated =3D false; > > > > > > > = > > > > > > > for_each_new_intel_crtc_in_state(state, crtc, > > > > > > > new_crtc_state, i) { > > > > > > > @@ -3883,6 +3884,12 @@ static int intel_compute_sagv_mask(str= uct intel_atomic_state *state) > > > > > > > = > > > > > > > old_bw_state =3D intel_atomic_get_old_bw_state(state); > > > > > > > = > > > > > > > + if (!active_pipes_calculated) { > > > > > > > + state->active_pipes =3D new_bw_state->active_pipes =3D > > > > > > = > > > > > > I don't think we should touch state->active_pipes here. > > > > > = > > > > > Well, that was my question actually here as well. I understand th= at changing > > > > > state->active_pipes here feels like some unneeded side effect, ho= wever having > > > > > state->active_pipes and bw_state->active_pipes going out of sync = doesn't sound > > > > > very attractive to me either. That is why I don't like this idea = of duplication > > > > > at all - having constant need to sync those state, bw_state, cdcl= k_state, because > > > > > they all might have different active_pipes now. > > > > = > > > > Having an out of date active_pipes anywhere would be a bug in that > > > > specific code. Also state->active_pipes is definitely going the way= of > > > > the dodo soon. > > > > = > > > > > = > > > > > > = > > > > > > > + intel_calc_active_pipes(state, old_bw_state->active_pipe= s); > > > > > > > + active_pipes_calculated =3D true; > > > > > > > + } > > > > > > = > > > > > > I'd do this after the loop so we don't need this extra boolean.= As far > > > > > > as the active_pipes check in intel_crtc_can_enable_sagv(), I th= ink we > > > > > > can pull it out into intel_compute_sagv_mask() so that we do th= e check > > > > > > after computing the mask. And of course change it to use > > > > > > bw_state->active_pipes instead. > > > > > = > > > > > intel_crtc_can_enable_sagv is called per crtc - so can't just pul= l it out, = > > > > > will have to have to cycles then - one will compute bw_state->act= ive_pipes, > > > > > and another pipe_sagv_mask. > > > > = > > > > Hmm. Actually I think what we should probably do is keep the > > > > active_pipes check in intel_can_enable_sagv(). Ie something like th= is: > > > > = > > > > intel_can_enable_sagv(bw_state) { > > > > if (active_pipes && !is_power_of_2(active_pipes)) > > > > return false; > > > > return sagv_reject !=3D 0; > > > > } > > > = > > > I need active_pipes check here for skl code only, as it disables SAGV= for multipipe > > > scenarios. Adding this here would generalize it for other platforms a= nd we > > > don't want that for ICL+. > > = > > Which is why I said "We can then make the check conditional on pre-icl > > (or whatever we want) in a later patch". Why in a later patch? Because > > currently the check is unconditional and it's generally a good idea to > > limit the number of functional changes per patch to a minimum. > = > Moving active_pipes check out of intel_crtc_can_enable_sagv will result > in wrong SAGV mask calculated. > = > i.e if you have 2 pipes, > = > for_each_crtc() { > if (crtc_can_sagv()) > sagv_reject &=3D ~pipe; > else > sagv_reject |=3D pipe; > } > = > will calculate sagv_reject as 0 which is wrong and value will be stored > in global state. No, it accurately reflects whether each of those pipes is capable of sagv. The single pipe restriction is an additinal constrain on top of that. In fact I think adjusting sagv_reject_mask based on this would result in the wrong value potentially. Consider for example: 1. Enable pipe A + B 2. sagv_reject would be calculated as 0x3 3. Disable pipe B 4. sagv_reject will have pipe B removed, leaving its value at 0x1 5. No SAGV even though we only have one pipe enabled, which is wrong > I think active_pipes should always affect the SAGV mask > otherwise we do get really strange situation: you have SAGV mask as 0, > but you still reject SAGV. So there is no way even then to track what = > was the previous SAGV state - even if it's 0 it could have been rejected. > = > IMO that is quite weird side effect. So removing active_pipes from > intel_crtc_can_enable_sagv doesn't sound like good idea. > = > I think it is now just a bit too much hassle around simple = > active_pipes_calculated boolean check. > = > Stan > = > > = > > > = > > > In fact that is the only reason I need active pipes here - otherwise = I think > > > it was even your comment that we actually don't need those here at al= l, > > > as we just iterate through crtcs in state - pretty clearly remember w= e discussed > > > this. Just same way how it's done in intel bw check and other places. > > > = > > > Stan > > > = > > > > = > > > > compute_sagv() { > > > > for_each_crtc() { > > > > if (crtc_can_sagv()) > > > > sagv_reject &=3D ~pipe; > > > > else > > > > sagv_reject |=3D pipe; > > > > } > > > > = > > > > active_pipes =3D calc_active_pipes(); > > > > = > > > > ... lock/serialize etc. > > > > } > > > > = > > > > That way we don't have to update sagv_reject at all based on > > > > active_pipes. I think that even makes more sense since the > > > > active_pipes check is a global thing and not tied to any specific > > > > crtc. > > > > = > > > > We can then make the check conditional on pre-icl (or whatever we w= ant) > > > > in a later patch. And finally we can remove it altogether in a sepa= rate > > > > patch, since I don't think we should have to do it on any platform. > > > > = > > > > > = > > > > > > = > > > > > > We're also going to need to lock_global_state() if bw_state->ac= tive_pipes > > > > > > mask changes. > > > > > = > > > > > Ohh.. right. > > > > > = > > > > > = > > > > > Stan > > > > > = > > > > > > = > > > > > > > + > > > > > > > if (intel_crtc_can_enable_sagv(new_crtc_state)) > > > > > > > new_bw_state->pipe_sagv_reject &=3D ~BIT(crtc->pipe); > > > > > > > else > > > > > > > @@ -5911,11 +5918,9 @@ skl_compute_wm(struct intel_atomic_sta= te *state) > > > > > > > if (ret) > > > > > > > return ret; > > > > > > > = > > > > > > > - if (state->modeset) { > > > > > > > - ret =3D intel_compute_sagv_mask(state); > > > > > > > - if (ret) > > > > > > > - return ret; > > > > > > > - } > > > > > > > + ret =3D intel_compute_sagv_mask(state); > > > > > > > + if (ret) > > > > > > > + return ret; > > > > > > = > > > > > > We also need to remove the state->modeset checks around > > > > > > sagv_{pre,post}_update(). > > > > > > = > > > > > > > = > > > > > > > /* > > > > > > > * skl_compute_ddb() will have adjusted the final watermarks > > > > > > > -- = > > > > > > > 2.24.1.485.gad05a3d8e5 > > > > > > = > > > > > > -- = > > > > > > Ville Syrj=E4l=E4 > > > > > > Intel > > > > = > > > > -- = > > > > Ville Syrj=E4l=E4 > > > > Intel > > = > > -- = > > Ville Syrj=E4l=E4 > > Intel -- = Ville Syrj=E4l=E4 Intel _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx