On Mon, 21 Mar 2022 at 19:21, Vinod Polimera <vpolimer@xxxxxxxxxxxxxxxx> wrote: > > > > > -----Original Message----- > > From: Stephen Boyd <swboyd@xxxxxxxxxxxx> > > Sent: Friday, March 18, 2022 2:41 AM > > To: quic_vpolimer <quic_vpolimer@xxxxxxxxxxx>; > > devicetree@xxxxxxxxxxxxxxx; dri-devel@xxxxxxxxxxxxxxxxxxxxx; > > freedreno@xxxxxxxxxxxxxxxxxxxxx; linux-arm-msm@xxxxxxxxxxxxxxx > > Cc: linux-kernel@xxxxxxxxxxxxxxx; robdclark@xxxxxxxxx; > > dmitry.baryshkov@xxxxxxxxxx; dianders@xxxxxxxxxxxx; quic_kalyant > > <quic_kalyant@xxxxxxxxxxx> > > Subject: Re: [PATCH v6 1/5] drm/msm/disp/dpu1: set mdp clk to the > > maximum frequency in opp table during probe > > > > WARNING: This email originated from outside of Qualcomm. Please be wary > > of any links or attachments, and do not enable macros. > > > > Quoting Vinod Polimera (2022-03-14 07:46:53) > > > use max clock during probe/bind sequence from the opp table. > > > The clock will be scaled down when framework sends an update. > > > > Capitalize 'use'. > > > > Why is it important to use max frequency during probe/bind? Does not > > setting the clk rate during probe mean that we'll never use the max > > rate? Does it speed things up during probe? > > We need to vote mdp clock during probe/bind so that rails are not set at undetermined state as pointed out by Dmitry. > Since we dont know what will be the rate set in boot loader, it would be ideal to vote at max frequency. > There could be a firmware display programmed in bootloader and we want to transition it to kernel without underflowing. This should be expressed in the commit message. -- With best wishes Dmitry
