On Thu, Jan 09, 2025 at 05:40:23PM -0800, Abhinav Kumar wrote:
>
>
> On 1/5/2025 7:07 PM, Dmitry Baryshkov wrote:
> > The fix_core_ab_vote is an average bandwidth value, used for bandwidth
> > overrides in several cases. However there is an internal inconsistency:
> > fix_core_ib_vote is defined in KBps, while fix_core_ab_vote is defined
> > in Bps.
> >
> > Fix that by changing the type of the variable to u32 and using * 1000ULL
> > multiplier when setting up the dpu_core_perf_params::bw_ctl value.
> >
>
> Actually after looking at this, I have another question.
>
> How did you conclude that fix_core_ib_vote is in KBps?
>
> min_dram_ib is in KBps in the catalog but how is fix_core_ib_vote?
>
> It depends on the interpretation perhaps. If the debugfs was supposed to
> operate under the expectation that the provided value will be pre-multiplied
> by 1000 and given then that explains why it was not multiplied again.
>
> And I cross-checked some of the internal usages of the debugfs, the values
> provided to it were in Bps and not KBps.
Well... As you wrote min_dram_ib is in KBps. So, by comparing the next
two lines, fix_core_ib_vote should also be in kBps, as there is no
premultiplier:
perf->max_per_pipe_ib = core_perf->fix_core_ib_vote;
[...]
perf->max_per_pipe_ib = perf_cfg->min_dram_ib;
And then, as a proof, perf->max_per_pipe_ib is passed to icc_set_bw()
without any modifications:
icc_set_bw(kms->path[i], avg_bw, perf.max_per_pipe_ib);
> > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> > ---
> > drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c | 4 ++--
> > drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.h | 2 +-
> > 2 files changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c
> > index 7263ab63a692554cd51a7fd91bd6250330179240..7cabc8f26908cfd2dbbffebd7c70fc37d9159733 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c
> > @@ -125,7 +125,7 @@ static void _dpu_core_perf_calc_crtc(const struct dpu_core_perf *core_perf,
> > perf->max_per_pipe_ib = 0;
> > perf->core_clk_rate = 0;
> > } else if (core_perf->perf_tune.mode == DPU_PERF_MODE_FIXED) {
> > - perf->bw_ctl = core_perf->fix_core_ab_vote;
> > + perf->bw_ctl = core_perf->fix_core_ab_vote * 1000ULL;
> > perf->max_per_pipe_ib = core_perf->fix_core_ib_vote;
> > perf->core_clk_rate = core_perf->fix_core_clk_rate;
> > } else {
> > @@ -479,7 +479,7 @@ int dpu_core_perf_debugfs_init(struct dpu_kms *dpu_kms, struct dentry *parent)
> > &perf->fix_core_clk_rate);
> > debugfs_create_u32("fix_core_ib_vote", 0600, entry,
> > &perf->fix_core_ib_vote);
> > - debugfs_create_u64("fix_core_ab_vote", 0600, entry,
> > + debugfs_create_u32("fix_core_ab_vote", 0600, entry,
> > &perf->fix_core_ab_vote);
> > return 0;
> > diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.h
> > index ca4595b4ec217697849af02446b23ed0857a0295..5e07119c14c6a9ed3413d0eaddbd93df5cc3f79d 100644
> > --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.h
> > +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.h
> > @@ -51,7 +51,7 @@ struct dpu_core_perf {
> > u32 enable_bw_release;
> > u64 fix_core_clk_rate;
> > u32 fix_core_ib_vote;
> > - u64 fix_core_ab_vote;
> > + u32 fix_core_ab_vote;
> > };
> > int dpu_core_perf_crtc_check(struct drm_crtc *crtc,
> >
--
With best wishes
Dmitry
