On Tue, 14 Jan 2025 at 03:31, Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> wrote:
>
>
>
> On 1/11/2025 5:08 AM, Dmitry Baryshkov wrote:
> > On 11 January 2025 01:49:23 EET, Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx> wrote:
> >>
> >>
> >> On 1/9/2025 6:02 PM, Dmitry Baryshkov wrote:
> >>> 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);
> >>>
> >>
> >> Understood max_per_pipe_ib. But then by the same logic, fix_core_ab_vote is always in Bps and not in KBps because bw_ctl is in Bps.
> >>
> >> Is it really a discrepancy that fix_core_ib_vote is defined in KBps, while fix_core_ab_vote is defined in Bps because they are just following the units in which bw_ctl and max_per_pipe_ib were defined in resp.
> >
> > Yes. They come in pair, as a part of the user interface. If one is in Bps and another one in KBps, it is very easy to forget that and misinterpret them or to make a mistake while programming them. Not to mention that the threshold files, which are related to AB, are in KBps.
> >
>
> In that case, the documentation for both needs to be updated as well as
> it still says both are in bps not kbps.
Ack, I missed it.
>
> * @fix_core_ib_vote: fixed core ib vote in bps used in mode 2
> * @fix_core_ab_vote: fixed core ab vote in bps used in mode 2
> */
> struct dpu_core_perf {
> const struct dpu_perf_cfg *perf_cfg;
> u64 core_clk_rate;
> u64 max_core_clk_rate;
> struct dpu_core_perf_tune perf_tune;
> u32 enable_bw_release;
> u64 fix_core_clk_rate;
> u64 fix_core_ib_vote;
> u64 fix_core_ab_vote;
> };
>
> >>
> >>>
> >>>>> 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
