[Intel-gfx] [CI 15/19] drm/i915/bigjoiner: atomic commit changes for uncompressed joiner
Manna, Animesh
animesh.manna at intel.com
Fri Jun 4 08:54:18 UTC 2021
> -----Original Message-----
> From: Jani Nikula <jani.nikula at linux.intel.com>
> Sent: Thursday, June 3, 2021 9:12 PM
> To: Manna, Animesh <animesh.manna at intel.com>; Roper, Matthew D
> <matthew.d.roper at intel.com>; intel-gfx at lists.freedesktop.org
> Cc: Navare, Manasi D <manasi.d.navare at intel.com>; Kulkarni, Vandita
> <vandita.kulkarni at intel.com>
> Subject: RE: [Intel-gfx] [CI 15/19] drm/i915/bigjoiner: atomic commit changes
> for uncompressed joiner
>
> On Thu, 03 Jun 2021, "Manna, Animesh" <animesh.manna at intel.com> wrote:
> >> -----Original Message-----
> >> From: Jani Nikula <jani.nikula at linux.intel.com>
> >> Sent: Thursday, June 3, 2021 3:10 PM
> >> To: Roper, Matthew D <matthew.d.roper at intel.com>; intel-
> >> gfx at lists.freedesktop.org
> >> Cc: Manna, Animesh <animesh.manna at intel.com>; Navare, Manasi D
> >> <manasi.d.navare at intel.com>; Kulkarni, Vandita
> >> <vandita.kulkarni at intel.com>
> >> Subject: Re: [Intel-gfx] [CI 15/19] drm/i915/bigjoiner: atomic commit
> >> changes for uncompressed joiner
> >>
> >> On Fri, 14 May 2021, Matt Roper <matthew.d.roper at intel.com> wrote:
> >> > From: Animesh Manna <animesh.manna at intel.com>
> >> >
> >> > Respective bit for master or slave to be set for uncompressed
> >> > bigjoiner in dss_ctl1 register.
> >>
> >> I was looking at the changes here due to a static checker complaint,
> >> and I think there are a number of issues here. Some more serious than
> >> others, and some predate the patch.
> >>
> >> Comments inline.
> >>
> >> > Cc: Manasi Navare <manasi.d.navare at intel.com>
> >> > Signed-off-by: Animesh Manna <animesh.manna at intel.com>
> >> > Signed-off-by: Clinton Taylor <Clinton.A.Taylor at intel.com>
> >> > Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
> >> > Reviewed-by: Manasi Navare <manasi.d.navare at intel.com>
> >> > ---
> >> > drivers/gpu/drm/i915/display/intel_display.c | 6 +++
> >> > drivers/gpu/drm/i915/display/intel_vdsc.c | 40 +++++++++++++++++++-
> >> > drivers/gpu/drm/i915/display/intel_vdsc.h | 2 +
> >> > drivers/gpu/drm/i915/i915_reg.h | 2 +
> >> > 4 files changed, 49 insertions(+), 1 deletion(-)
> >> >
> >> > diff --git a/drivers/gpu/drm/i915/display/intel_display.c
> >> > b/drivers/gpu/drm/i915/display/intel_display.c
> >> > index b5fd721137d3..422b59ebf6dc 100644
> >> > --- a/drivers/gpu/drm/i915/display/intel_display.c
> >> > +++ b/drivers/gpu/drm/i915/display/intel_display.c
> >> > @@ -3411,6 +3411,7 @@ static void
> >> > icl_ddi_bigjoiner_pre_enable(struct
> >> intel_atomic_state *state,
> >> > const struct intel_crtc_state
> >> *crtc_state) {
> >> > struct intel_crtc *master = to_intel_crtc(crtc_state->uapi.crtc);
> >> > + struct drm_i915_private *dev_priv = to_i915(master->base.dev);
> >> > struct intel_crtc_state *master_crtc_state;
> >> > struct drm_connector_state *conn_state;
> >> > struct drm_connector *conn;
> >> > @@ -3444,6 +3445,9 @@ static void
> >> > icl_ddi_bigjoiner_pre_enable(struct
> >> intel_atomic_state *state,
> >> > /* and DSC on slave */
> >> > intel_dsc_enable(NULL, crtc_state);
> >> > }
> >> > +
> >> > + if (DISPLAY_VER(dev_priv) >= 13)
> >> > + intel_uncompressed_joiner_enable(crtc_state);
> >> > }
> >> >
> >> > static void hsw_crtc_enable(struct intel_atomic_state *state, @@
> >> > -6250,6 +6254,8 @@ static bool hsw_get_pipe_config(struct intel_crtc
> *crtc,
> >> > }
> >> >
> >> > intel_dsc_get_config(pipe_config);
> >> > + if (DISPLAY_VER(dev_priv) >= 13 && !pipe_config-
> >> >dsc.compression_enable)
> >> > + intel_uncompressed_joiner_get_config(pipe_config);
> >> >
> >> > if (!active) {
> >> > /* bigjoiner slave doesn't enable transcoder */ diff --git
> >> > a/drivers/gpu/drm/i915/display/intel_vdsc.c
> >> > b/drivers/gpu/drm/i915/display/intel_vdsc.c
> >> > index adcd6752f919..efc3184d8315 100644
> >> > --- a/drivers/gpu/drm/i915/display/intel_vdsc.c
> >> > +++ b/drivers/gpu/drm/i915/display/intel_vdsc.c
> >> > @@ -1021,6 +1021,22 @@ static i915_reg_t dss_ctl2_reg(const struct
> >> intel_crtc_state *crtc_state)
> >> > return is_pipe_dsc(crtc_state) ? ICL_PIPE_DSS_CTL2(pipe) :
> >> > DSS_CTL2; }
> >> >
> >> > +void intel_uncompressed_joiner_enable(const struct
> >> > +intel_crtc_state
> >> > +*crtc_state)
> >>
> >> Naming. Basically for any new function, the function name prefix
> >> should match the file name. intel_vdsc.[ch] should have functions
> >> prefixed intel_vdsc_*(). This is where we're headed to increase clarity.
> >>
> >> intel_uncompressed_*() is something completely different.
> >>
> >> Granted, here we already have intel_dsc_*() in intel_vdsc.c. We
> >> should probably stick with intel_dsc_*(). A possible function or file
> >> rename is not out of the question, but that's a separate matter.
> >
> > As there is not separate register for uncompressed joiner, using bitfield of dsc
> register only the function name can be changed to
> intel_dsc_uncompressed_joiner_enable().
> >
> >>
> >> > +{
> >> > + struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> >> > + struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> >> > + u32 dss_ctl1_val = 0;
> >> > +
> >> > + if (crtc_state->bigjoiner && !crtc_state->dsc.compression_enable) {
> >> > + if (crtc_state->bigjoiner_slave)
> >> > + dss_ctl1_val |= UNCOMPRESSED_JOINER_SLAVE;
> >> > + else
> >> > + dss_ctl1_val |= UNCOMPRESSED_JOINER_MASTER;
> >> > +
> >> > + intel_de_write(dev_priv, dss_ctl1_reg(crtc_state), dss_ctl1_val);
> >> > + }
> >> > +}
> >> > +
> >> > void intel_dsc_enable(struct intel_encoder *encoder,
> >> > const struct intel_crtc_state *crtc_state) { @@ -1060,13
> >> > +1076,35 @@ void intel_dsc_disable(const struct intel_crtc_state
> >> *old_crtc_state)
> >> > struct intel_crtc *crtc = to_intel_crtc(old_crtc_state->uapi.crtc);
> >> > struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> >> >
> >> > - if (!old_crtc_state->dsc.compression_enable)
> >> > + if (!(old_crtc_state->dsc.compression_enable &&
> >> > + old_crtc_state->bigjoiner))
> >>
> >> This fails to disable compression if we only have compression but no
> >> bigjoiner, which is the more common case!
> >>
> >> See also:
> >>
> >> https://gitlab.freedesktop.org/drm/intel/-/issues/3537
> >> https://patchwork.freedesktop.org/patch/msgid/20210603065356.15435-1-
> >> vandita.kulkarni at intel.com
> >>
> >
> > We may need to remove both the condition check.
> > In uncompressed bigjoiner, compression_enable flag will be 0 and may not
> clear the bit of dss_ctl1_reg.
> > So can we remove both the checks, hoping it will not harm reseting the
> register even if it is not set.
>
> Now it only disables if *both* were enabled. It needs to be disabled if
> *either* was enabled. But if *neither* was enabled, we don't need to do this.
Ok.
>
>
> >
> >> > return;
> >> >
> >> > intel_de_write(dev_priv, dss_ctl1_reg(old_crtc_state), 0);
> >> > intel_de_write(dev_priv, dss_ctl2_reg(old_crtc_state), 0); }
> >> >
> >> > +void intel_uncompressed_joiner_get_config(struct intel_crtc_state
> >> > +*crtc_state) {
> >> > + struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
> >> > + struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> >> > + u32 dss_ctl1;
> >> > +
> >> > + dss_ctl1 = intel_de_read(dev_priv, dss_ctl1_reg(crtc_state));
> >> > + if (dss_ctl1 & UNCOMPRESSED_JOINER_MASTER) {
> >> > + crtc_state->bigjoiner = true;
> >> > + if (!WARN_ON(INTEL_NUM_PIPES(dev_priv) == crtc->pipe + 1))
> >> > + crtc_state->bigjoiner_linked_crtc =
> >> > + intel_get_crtc_for_pipe(dev_priv, crtc->pipe +
> >> 1);
> >> > + } else if (dss_ctl1 & UNCOMPRESSED_JOINER_SLAVE) {
> >> > + crtc_state->bigjoiner = true;
> >> > + crtc_state->bigjoiner_slave = true;
> >> > + if (!WARN_ON(crtc->pipe == PIPE_A))
> >> > + crtc_state->bigjoiner_linked_crtc =
> >> > + intel_get_crtc_for_pipe(dev_priv, crtc->pipe -
> >> 1);
> >> > + }
> >>
> >> Nitpick: This duplicates a bunch of logic for figuring out master/slave.
> >>
> >> The static checker warning was about crtc->pipe + 1 usage. Since
> >> INTEL_NUM_PIPES() looks at the hamming weight of i915->pipe_mask, the
> >> checker has a hard time figuring out it does not overflow
> >> i915->pipe_to_crtc_mapping[] in intel_get_crtc_for_pipe().
> >>
> >> So here in intel_vdsc.c the checks are for overflowing/underflowing
> >> the pipe range. In intel_get_crtc_for_pipe() there's a check for the
> >> pipe actually existing - the pipe numbering might not be contiguous.
> >>
> >> Superficially the static checker warning is bogus, as in we won't
> >> overflow anything. However, deep down there are issues in the
> >> consistency of the checks and how to handle non-contigouous pipe
> numbering.
> >>
> >> Indeed, this does not *need* the number. We should figure out the
> >> next *crtc*, not the next pipe *number*, which may or may not be pipe + 1.
> >
> > dss_ctl1 value is used to identify master or slave crtc. If needed WARN_ON
> check can be removed... but pipe enum values like PIPE_A/B/C/D is used to get
> the master/slave crtc and always bigjoiner is possible with two adjacent pipes.
>
> I sent the patch for this and you reviewed it... but are adjacent pipes a
> requirement for bigjoiner? Would e.g. A+C work if B was fused off? If not, my
> patch 2/2 is incorrect.
Yes, I am also tried to check again in bspec. Adjacent pipe is needed for bigjoiner though have not mentioned anything in case of pipe fusing.
Regards,
Animesh
>
> BR,
> Jani.
>
>
> >
> > Regards,
> > Animesh
> >
> >>
> >>
> >> BR,
> >> Jani.
> >>
> >> > +}
> >> > +
> >> > void intel_dsc_get_config(struct intel_crtc_state *crtc_state) {
> >> > struct drm_dsc_config *vdsc_cfg = &crtc_state->dsc.config; diff
> >> > --git a/drivers/gpu/drm/i915/display/intel_vdsc.h
> >> > b/drivers/gpu/drm/i915/display/intel_vdsc.h
> >> > index 65d301c23580..fe4d45561253 100644
> >> > --- a/drivers/gpu/drm/i915/display/intel_vdsc.h
> >> > +++ b/drivers/gpu/drm/i915/display/intel_vdsc.h
> >> > @@ -12,11 +12,13 @@ struct intel_encoder; struct intel_crtc_state;
> >> >
> >> > bool intel_dsc_source_support(const struct intel_crtc_state
> >> > *crtc_state);
> >> > +void intel_uncompressed_joiner_enable(const struct
> >> > +intel_crtc_state *crtc_state);
> >> > void intel_dsc_enable(struct intel_encoder *encoder,
> >> > const struct intel_crtc_state *crtc_state); void
> >> > intel_dsc_disable(const struct intel_crtc_state *crtc_state); int
> >> > intel_dsc_compute_params(struct intel_encoder *encoder,
> >> > struct intel_crtc_state *pipe_config);
> >> > +void intel_uncompressed_joiner_get_config(struct intel_crtc_state
> >> > +*crtc_state);
> >> > void intel_dsc_get_config(struct intel_crtc_state *crtc_state);
> >> > enum intel_display_power_domain intel_dsc_power_domain(const
> >> > struct intel_crtc_state *crtc_state); diff --git
> >> > a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> >> > index 31bc413dbba1..dd6e0bae9573 100644
> >> > --- a/drivers/gpu/drm/i915/i915_reg.h
> >> > +++ b/drivers/gpu/drm/i915/i915_reg.h
> >> > @@ -11493,6 +11493,8 @@ enum skl_power_gate {
> >> > #define SPLITTER_CONFIGURATION_MASK REG_GENMASK(26, 25)
> >> > #define SPLITTER_CONFIGURATION_2_SEGMENT
> >> REG_FIELD_PREP(SPLITTER_CONFIGURATION_MASK, 0)
> >> > #define SPLITTER_CONFIGURATION_4_SEGMENT
> >> REG_FIELD_PREP(SPLITTER_CONFIGURATION_MASK, 1)
> >> > +#define UNCOMPRESSED_JOINER_MASTER (1 << 21)
> >> > +#define UNCOMPRESSED_JOINER_SLAVE (1 << 20)
> >> >
> >> > #define _ICL_PIPE_DSS_CTL2_PB 0x78204
> >> > #define _ICL_PIPE_DSS_CTL2_PC 0x78404
> >>
> >> --
> >> Jani Nikula, Intel Open Source Graphics Center
>
> --
> Jani Nikula, Intel Open Source Graphics Center
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