On Tue, Feb 01, 2022 at 01:18:18PM +0200, Lisovskiy, Stanislav wrote: > On Tue, Feb 01, 2022 at 12:05:13PM +0200, Ville Syrjälä wrote: > > On Tue, Feb 01, 2022 at 10:52:39AM +0200, Lisovskiy, Stanislav wrote: > > > On Tue, Jan 18, 2022 at 11:23:50AM +0200, Ville Syrjala wrote: > > > > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > > > > > > > intel_bw_calc_min_cdclk() is entirely pointless. All it manages to do is > > > > somehow conflate the per-pipe min cdclk with dbuf min cdclk. There is no > > > > (at least documented) dbuf min cdclk limit on pre-skl so let's just get > > > > rid of all this confusion. > > > > > > > > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > > > > > I think we constantly have a bit contradictional attitude towards such situation. > > > >From one perspective you can say, that those kind of "leagcy" callbacks are > > > pointless, from the other hand one might say. that we need to have a unified > > > approach for all platforms and I think we got, some legacy handlers for old > > > platforms for similar purpose as well. > > > I'm fine with both approaches, however for example when I was submitting > > > that patch, I was asked by reviewer to add this kind of legacy callback, so that we have > > > a "uniform" approach. > > > We just then need to have some standard agreement on those, which doesn't > > > depend on today's cosmic radiation levels :) > > > > Yes in general I prefer a unified approach across all platforms. > > But in this case there is nothing to do for the old platforms as they > > don't have any kind of dbuf cdclk limit, or if there is one we don't > > know what it is since it's not documented. > > > > So the only thing the code was really doing was conflating the > > per-pipe cdclk limit (which is handled elsewhere for all platforms > > in a unified fashion) with something that doesn't even exist. > > > > Also I don't think it was even correct anyway since it was > > using the per-pipe cdclk_state->min_cdclk[] already during > > intel_cdclk_atomic_check(), but cdclk_state->min_cdclk[] > > isn't even computed until intel_modeset_calc_cdclk() which > > is called later. So I guess it was basically just computing > > the max of the min_cdclk[] for all the pipes for the _old_ > > state, not the new state. > > No, I think actually the idea was that it was first calculating > new_bw_state->min_cdclk, based on plane and dbuf bandwidth requirements > in intel_atomic_check_cdclk, Well intel_bw_calc_min_cdclk() did none of that. Like I said it just took the max of the _old_ per-pipe cdclk_state->min_cdclk[] values and stored that as the *new* bw min cdclk, which later would get consulted by intel_compute_min_cdclk(). -- Ville Syrjälä Intel
