> -----Original Message-----
> From: Nikula, Jani <jani.nikula@xxxxxxxxx>
> Sent: Monday, February 24, 2025 4:18 PM
> To: Manna, Animesh <animesh.manna@xxxxxxxxx>; intel-
> gfx@xxxxxxxxxxxxxxxxxxxxx; intel-xe@xxxxxxxxxxxxxxxxxxxxx
> Cc: Hogander, Jouni <jouni.hogander@xxxxxxxxx>; B, Jeevan
> <jeevan.b@xxxxxxxxx>; Manna, Animesh <animesh.manna@xxxxxxxxx>
> Subject: Re: [PATCH v4 4/8] drm/i915/lobf: Update lobf if any change in
> dependent parameters
>
> On Mon, 24 Feb 2025, Animesh Manna <animesh.manna@xxxxxxxxx> wrote:
> > For every commit the dependent condition for LOBF is checked and
> > accordingly update has_lobf flag which will be used to update the
> > ALPM_CTL register during commit.
> >
> > Signed-off-by: Animesh Manna <animesh.manna@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/display/intel_alpm.c | 16 ++++++++++++++++
> > drivers/gpu/drm/i915/display/intel_alpm.h | 1 +
> > drivers/gpu/drm/i915/display/intel_ddi.c | 2 ++
> > 3 files changed, 19 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_alpm.c
> > b/drivers/gpu/drm/i915/display/intel_alpm.c
> > index 1438e125cde1..83719ee1721c 100644
> > --- a/drivers/gpu/drm/i915/display/intel_alpm.c
> > +++ b/drivers/gpu/drm/i915/display/intel_alpm.c
> > @@ -312,6 +312,22 @@ void intel_alpm_lobf_compute_config(struct
> intel_dp *intel_dp,
> > (first_sdp_position + waketime_in_lines); }
> >
> > +void intel_alpm_lobf_update(const struct intel_crtc_state
> > +*crtc_state) {
> > + struct intel_display *display = to_intel_display(crtc_state);
> > + enum transcoder cpu_transcoder = crtc_state->cpu_transcoder;
> > + u32 alpm_ctl;
> > +
> > + if (DISPLAY_VER(display) < 20)
> > + return;
> > +
> > + alpm_ctl = intel_de_read(display, ALPM_CTL(display,
> cpu_transcoder));
> > + if (alpm_ctl & ALPM_CTL_LOBF_ENABLE && !crtc_state->has_lobf) {
>
> You don't need to even read the register if crtc_state->has_lobf is true.
Thanks Jani for review.
Reading register to get what is there in ALPM_CTL register, like aux-less or aux-wake alpm and etc.
For LOBF we need to touch a specific bit, and don't want to modify other bitfields.
Regards,
Animesh
>
> > + alpm_ctl &= ~ALPM_CTL_LOBF_ENABLE;
> > + intel_de_write(display, ALPM_CTL(display, cpu_transcoder),
> alpm_ctl);
> > + }
> > +}
> > +
> > static void lnl_alpm_configure(struct intel_dp *intel_dp,
> > const struct intel_crtc_state *crtc_state) { diff --
> git
> > a/drivers/gpu/drm/i915/display/intel_alpm.h
> > b/drivers/gpu/drm/i915/display/intel_alpm.h
> > index 91f51fb24f98..c6efd25c2062 100644
> > --- a/drivers/gpu/drm/i915/display/intel_alpm.h
> > +++ b/drivers/gpu/drm/i915/display/intel_alpm.h
> > @@ -23,6 +23,7 @@ void intel_alpm_lobf_compute_config(struct intel_dp
> *intel_dp,
> > struct drm_connector_state *conn_state);
> void
> > intel_alpm_configure(struct intel_dp *intel_dp,
> > const struct intel_crtc_state *crtc_state);
> > +void intel_alpm_lobf_update(const struct intel_crtc_state
> > +*crtc_state);
> > void intel_alpm_post_plane_update(struct intel_atomic_state *state,
> > struct intel_crtc *crtc);
> > void intel_alpm_lobf_debugfs_add(struct intel_connector *connector);
> > diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c
> > b/drivers/gpu/drm/i915/display/intel_ddi.c
> > index 26aa32d4d50e..44258ba0d951 100644
> > --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> > @@ -37,6 +37,7 @@
> > #include "icl_dsi.h"
> > #include "intel_alpm.h"
> > #include "intel_audio.h"
> > +#include "intel_alpm.h"
> > #include "intel_audio_regs.h"
> > #include "intel_backlight.h"
> > #include "intel_combo_phy.h"
> > @@ -3621,6 +3622,7 @@ static void intel_ddi_update_pipe_dp(struct
> intel_atomic_state *state,
> > intel_ddi_set_dp_msa(crtc_state, conn_state);
> >
> > intel_dp_set_infoframes(encoder, true, crtc_state, conn_state);
> > + intel_alpm_lobf_update(crtc_state);
> >
> > intel_backlight_update(state, encoder, crtc_state, conn_state);
> > drm_connector_update_privacy_screen(conn_state);
>
> --
> Jani Nikula, Intel
