On Thu, 03 Jun 2021, "Navare, Manasi" <manasi.d.navare@xxxxxxxxx> wrote:
> On Thu, Jun 03, 2021 at 06:49:23AM -0700, Manna, Animesh wrote:
>>
>>
>> > -----Original Message-----
>> > From: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
>> > Sent: Thursday, June 3, 2021 6:03 PM
>> > To: Roper, Matthew D <matthew.d.roper@xxxxxxxxx>; intel-
>> > gfx@xxxxxxxxxxxxxxxxxxxxx
>> > Cc: Manna, Animesh <animesh.manna@xxxxxxxxx>; Navare, Manasi D
>> > <manasi.d.navare@xxxxxxxxx>; Kulkarni, Vandita <vandita.kulkarni@xxxxxxxxx>
>> > Subject: Re: [CI 15/19] drm/i915/bigjoiner: atomic commit changes
>> > for uncompressed joiner
>> >
>> > On Thu, 03 Jun 2021, Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx> wrote:
>> > > On Fri, 14 May 2021, Matt Roper <matthew.d.roper@xxxxxxxxx> wrote:
>> > >> From: Animesh Manna <animesh.manna@xxxxxxxxx>
>> > >>
>> > >> 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@xxxxxxxxx>
>> > >> Signed-off-by: Animesh Manna <animesh.manna@xxxxxxxxx>
>> > >> Signed-off-by: Clinton Taylor <Clinton.A.Taylor@xxxxxxxxx>
>> > >> Signed-off-by: Matt Roper <matthew.d.roper@xxxxxxxxx>
>> > >> Reviewed-by: Manasi Navare <manasi.d.navare@xxxxxxxxx>
>> > >> ---
>> > >> 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)
>> >
>> > I don't think we should add these checks here. Make sure the crtc_state only has
>> > the relevant stuff enabled if the platform supports it. Don't duplicate the checks.
>>
>> Agree.
>
>
>>
>> >
>> > >> + intel_uncompressed_joiner_enable(crtc_state);
>> >
>> > As this is always called after intel_dsc_enable(), I think it would make sense to
>> > move this within intel_dsc_enable().
>>
>> Agree.
>
> @Jani I had asked to create a separate joiner enable since having an uncompressed enable inside dsc_enable
> just from the names makes it contradicting.
> But sure may be with a comment before calling uncompressed_joiner_enable() it can be just called from inside dsc enable()
> And instead of checking the display ver there we just use this condition:
> if (crtc_state->bigjoiner && !crtc_state->dsc.compression_enable) {
> intel_uncompressed_joiner_enable(crtc_state);
> }
> Since the atomic check ensures that only for ver >=13 is when we allow big joiner and no DSC combination.
>
> Animesh, Jani does that sound good?
Yes.
Regarding naming semantics, I think we just need to consider DSC an
engine that does other things than just compression. The actual
registers being the same makes, I think, the logic harder to follow with
these being separate steps. Also, you can then cover them with a single
power domain get/put.
Anyway, care must be taken to not change the logic for compressed paths.
BR,
Jani.
>
> Manasi
>
>
>> >
>> > >> }
>> > >>
>> > >> 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);
>> >
>> > As this is always called after intel_dsc_get_config(), I think it would make sense
>> > to move this within intel_dsc_get_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.
>> > >
>> > >> +{
>> > >> + 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-v
>> > > andita.kulkarni@xxxxxxxxx
>> > >
>> > >> 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));
>> >
>> > You can't read this without holding the power domain.
>> >
>> > Since this is always called after intel_dsc_get_config(), I think it would make
>> > sense to move this reading there.
>>
>> Ok.
>> Earlier the plan is to have separate functions for uncompressed joiner, but as you suggested it can be done in the same functions of compressed bigjoiner code.
>> Thanks Jani for review.
>>
>> Regards,
>> Animesh
>>
>> >
>> > >> + 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.
>> > >
>> > >
>> > > 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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