[Freedreno] [PATCH 0/5] MDSS reg bus interconnect

[Dmitry Baryshkov]

On Wed, 19 Apr 2023 at 21:50, Jeykumar Sankaran
<quic_jeykumar at quicinc.com> wrote:
>
>
>
> On 4/17/2023 8:30 AM, Konrad Dybcio wrote:
> > Apart from the already handled data bus (MAS_MDP_Pn<->DDR), there's
> > another path that needs to be handled to ensure MDSS functions properly,
> > namely the "reg bus", a.k.a the CPU-MDSS interconnect.
> >
> > Gating that path may have a variety of effects.. from none to otherwise
> > inexplicable DSI timeouts..
> >
> Current DPU driver already votes on the "reg bus" indirectly through the
> display AHB clock handle[<&dispcc DISP_CC_MDSS_AHB_CLK>] in DTSI. Can
> you provide more details on the issues that warrants this patch series?

Does that mean that if we cast a proper vote on the SLAVE_DISPLAY_CFG,
we can drop the DISP_CC_MDSS_AHB_CLK clock?

Also, I'd like to point out that SDE does both things: it casts the <1
590 xxx yyy> bus votes and enables the DISP_CC_MDSS_AHB_CLK clock.


>
> > This series tries to address the lack of that.
> >
> > Example path:
> >
> > interconnects = <&bimc MASTER_AMPSS_M0 0 &config_noc SLAVE_DISPLAY_CFG 0>;
> >
> > Signed-off-by: Konrad Dybcio <konrad.dybcio at linaro.org>
> > ---
> > Konrad Dybcio (5):
> >        dt-bindings: display/msm: Add reg bus interconnect
> >        drm/msm/dpu1: Rename path references to mdp_path
> >        drm/msm/mdss: Rename path references to mdp_path
> >        drm/msm/mdss: Handle the reg bus ICC path
> >        drm/msm/dpu1: Handle the reg bus ICC path
> >
> >   .../bindings/display/msm/mdss-common.yaml          |  1 +
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_core_perf.c      | 10 +++----
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c            | 34 ++++++++++++++++-----
> >   drivers/gpu/drm/msm/disp/dpu1/dpu_kms.h            |  5 ++--
> >   drivers/gpu/drm/msm/msm_mdss.c                     | 35 ++++++++++++++--------
> >   5 files changed, 57 insertions(+), 28 deletions(-)
> > ---
> > base-commit: d3f2cd24819158bb70701c3549e586f9df9cee67
> > change-id: 20230417-topic-dpu_regbus-abc94a770952
> >
> > Best regards,



-- 
With best wishes
Dmitry