Re: [PATCH 16/19] drm/i915: Add new abstraction layer to handle pipe order for different joiners

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Mon, Sep 16, 2024 at 01:09:42PM +0530, Nautiyal, Ankit K wrote:
> 
> On 9/12/2024 4:08 AM, Ville Syrjälä wrote:
> > On Wed, Sep 11, 2024 at 06:43:46PM +0530, Ankit Nautiyal wrote:
> >> From: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
> >>
> >> Ultrajoiner case requires special treatment where both reverse and
> >> staight order iteration doesn't work(for instance disabling case requires
> >> order to be: primary master, slaves, secondary master).
> >>
> >> Lets unify our approach by using not only pipe masks for iterating required
> >> pipes based on joiner type used, but also using different "priority" arrays
> >> for each of those.
> >>
> >> v2: Fix checkpatch warnings. (Ankit)
> >>
> >> Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
> >> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> >> ---
> >>   drivers/gpu/drm/i915/display/intel_ddi.c     | 19 +++--
> >>   drivers/gpu/drm/i915/display/intel_display.c | 83 ++++++++++++++++----
> >>   drivers/gpu/drm/i915/display/intel_display.h |  7 ++
> >>   drivers/gpu/drm/i915/display/intel_dp_mst.c  | 18 +++--
> >>   4 files changed, 96 insertions(+), 31 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c b/drivers/gpu/drm/i915/display/intel_ddi.c
> >> index 00fbe9f8c03a..2c064b6c6d01 100644
> >> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> >> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> >> @@ -3116,10 +3116,11 @@ static void intel_ddi_post_disable_hdmi_or_sst(struct intel_atomic_state *state,
> >>   					       const struct drm_connector_state *old_conn_state)
> >>   {
> >>   	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
> >> -	struct intel_crtc *pipe_crtc;
> >> +	struct intel_crtc *pipe_crtc; enum pipe pipe;
> >>   
> >> -	for_each_intel_crtc_in_pipe_mask(&dev_priv->drm, pipe_crtc,
> >> -					 intel_crtc_joined_pipe_mask(old_crtc_state)) {
> >> +	for_each_intel_crtc_in_mask_priority(dev_priv, pipe_crtc, pipe,
> >> +					     intel_crtc_joined_pipe_mask(old_crtc_state),
> >> +					     intel_get_pipe_order_disable(old_crtc_state)) {
> >>   		const struct intel_crtc_state *old_pipe_crtc_state =
> >>   			intel_atomic_get_old_crtc_state(state, pipe_crtc);
> >>   
> >> @@ -3130,8 +3131,9 @@ static void intel_ddi_post_disable_hdmi_or_sst(struct intel_atomic_state *state,
> >>   
> >>   	intel_ddi_disable_transcoder_func(old_crtc_state);
> >>   
> >> -	for_each_intel_crtc_in_pipe_mask(&dev_priv->drm, pipe_crtc,
> >> -					 intel_crtc_joined_pipe_mask(old_crtc_state)) {
> >> +	for_each_intel_crtc_in_mask_priority(dev_priv, pipe_crtc, pipe,
> >> +					     intel_crtc_joined_pipe_mask(old_crtc_state),
> >> +					     intel_get_pipe_order_disable(old_crtc_state)) {
> >>   		const struct intel_crtc_state *old_pipe_crtc_state =
> >>   			intel_atomic_get_old_crtc_state(state, pipe_crtc);
> >>   
> >> @@ -3383,7 +3385,7 @@ static void intel_enable_ddi(struct intel_atomic_state *state,
> >>   			     const struct drm_connector_state *conn_state)
> >>   {
> >>   	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
> >> -	struct intel_crtc *pipe_crtc;
> >> +	struct intel_crtc *pipe_crtc; enum pipe pipe;
> >>   
> >>   	intel_ddi_enable_transcoder_func(encoder, crtc_state);
> >>   
> >> @@ -3394,8 +3396,9 @@ static void intel_enable_ddi(struct intel_atomic_state *state,
> >>   
> >>   	intel_ddi_wait_for_fec_status(encoder, crtc_state, true);
> >>   
> >> -	for_each_intel_crtc_in_pipe_mask_reverse(&i915->drm, pipe_crtc,
> >> -						 intel_crtc_joined_pipe_mask(crtc_state)) {
> >> +	for_each_intel_crtc_in_mask_priority(i915, pipe_crtc, pipe,
> >> +					     intel_crtc_joined_pipe_mask(crtc_state),
> >> +					     intel_get_pipe_order_enable(crtc_state)) {
> >>   		const struct intel_crtc_state *pipe_crtc_state =
> >>   			intel_atomic_get_new_crtc_state(state, pipe_crtc);
> >>   
> >> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> >> index db27850b2c36..27622d51a473 100644
> >> --- a/drivers/gpu/drm/i915/display/intel_display.c
> >> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> >> @@ -1737,6 +1737,50 @@ static void hsw_configure_cpu_transcoder(const struct intel_crtc_state *crtc_sta
> >>   	hsw_set_transconf(crtc_state);
> >>   }
> >>   
> >> +static
> >> +bool intel_crtc_is_bigjoiner(const struct intel_crtc_state *pipe_config)
> >> +{
> >> +	return hweight8(pipe_config->joiner_pipes) == 2;
> >> +}
> >> +
> >> +const enum pipe *intel_get_pipe_order_enable(const struct intel_crtc_state *crtc_state)
> >> +{
> >> +	static const enum pipe ultrajoiner_pipe_order_enable[I915_MAX_PIPES] = {
> >> +		PIPE_B, PIPE_D, PIPE_C, PIPE_A
> >> +	};
> >> +	static const enum pipe bigjoiner_pipe_order_enable[I915_MAX_PIPES] = {
> >> +		PIPE_B, PIPE_A, PIPE_D, PIPE_C
> >> +	};
> >> +	static const enum pipe nojoiner_pipe_order_enable[I915_MAX_PIPES] = {
> >> +		PIPE_A, PIPE_B, PIPE_C, PIPE_D
> >> +	};
> >> +
> >> +	if (intel_crtc_is_ultrajoiner(crtc_state))
> >> +		return ultrajoiner_pipe_order_enable;
> >> +	else if (intel_crtc_is_bigjoiner(crtc_state))
> >> +		return bigjoiner_pipe_order_enable;
> >> +	return nojoiner_pipe_order_enable;
> >> +}
> >> +
> >> +const enum pipe *intel_get_pipe_order_disable(const struct intel_crtc_state *crtc_state)
> >> +{
> >> +	static const enum pipe ultrajoiner_pipe_order_disable[I915_MAX_PIPES] = {
> >> +		PIPE_A, PIPE_B, PIPE_D, PIPE_C
> >> +	};
> >> +	static const enum pipe bigjoiner_pipe_order_disable[I915_MAX_PIPES] = {
> >> +		PIPE_A, PIPE_B, PIPE_C, PIPE_D
> >> +	};
> >> +	static const enum pipe nojoiner_pipe_order_disable[I915_MAX_PIPES] = {
> >> +		PIPE_A, PIPE_B, PIPE_C, PIPE_D
> >> +	};
> >> +
> >> +	if (intel_crtc_is_ultrajoiner(crtc_state))
> >> +		return ultrajoiner_pipe_order_disable;
> >> +	else if (intel_crtc_is_bigjoiner(crtc_state))
> >> +		return bigjoiner_pipe_order_disable;
> >> +	return nojoiner_pipe_order_disable;
> > I don't think we should need all those diffrent order array. Technically
> > one should do. Though having two might make sense.
> >
> > Another problem is the hardcoded pipes. If we eg. get hardware that
> > would support ultrajoiner on pipes B-E in the future this would no
> > longer  work.
> >
> >> +}
> > <snip>
> >> +#define for_each_intel_crtc_in_mask_priority(__dev_priv, intel_crtc, __p, __mask, __priolist) \
> >> +	for_each_pipe(__dev_priv, __p) \
> >> +		for_each_if((__mask) & BIT(__priolist[__p])) \
> >> +			for_each_if(intel_crtc = intel_crtc_for_pipe(to_intel_display(&__dev_priv->drm), __priolist[__p]))
> >
> > I think something like:
> >
> > const u8 intel_pipe_order_enable[4] = {
> >          3, 1, 2, 0,
> > };
> >
> > const u8 intel_pipe_order_disable[4] = {
> >          0, 2, 1, 3,
> > };
> >
> > #define for_each_intel_crtc_in_pipe_mask_ordered(crtc, pipe_masks, order, i) \
> >          for ((i) = 0; \
> >               (i) < ARRAY_SIZE(order) && \
> >               ((crtc) = intel_crtc_for_pipe(joiner_primary_pipe(pipe_mask) + (order)[(i)]), 1); \
> >               (i)++) \
> >                  for_each_if((crtc) && (pipe_mask) & BIT((crtc)->pipe))
> >
> > would let us avoid that hardcoded pipe stuff, and everything is
> > just based on the relative order between the pipes. The same orders
> > also work for bigjoiner and non-joined cases (it just skips the pipes
> > that are't in the mask).
> >
> >
> > The alternative would be to just use the bigjoiner primary+secondary masks
> > and come up with a a way to iterate two bitmask in either forward or reverse
> > order. Hmm, I suppose one might just combine the bigjoiner primary and
> > secondary masks into one, with one of them shifted up to some high bits,
> > and then iterate the combined bitmask either forward or backward.
> >
> > Something like this should work:
> > #define for_each_crtc_in_masks(crtc, first_pipes, second_pipes, pipes, i) \
> >          for ((i) = 0, (pipes) = (second_pipes) << 16 | (first_pipes); \
> >               (i) < 32 && ((crtc) = intel_crtc_for_pipe((i) & 15), 1); \
> >               (i)++) \
> >                  for_each_if((crtc) && (pipes) & BIT(i))
> >
> > #define for_each_crtc_in_masks_reverse(crtc, first_pipes, second_pipes, pipes, i) \
> >          for ((i) = 31, (pipes) = (first_pipes) << 16 | (second_pipes); \
> >               (i) >= 0 && ((crtc) = intel_crtc_for_pipe((i) & 15), 1); \
> >               (i)--) \
> >                  for_each_if((crtc) && (pipes) & BIT(i))
> >
> > (could reduce the constants a bit given we don't have 16 pipes).
> 
> This looks good to me. changed for 4 pipes, as below:
> 
> 
> #define for_each_crtc_in_masks(crtc, first_pipes, second_pipes, pipes, i) \
>          for ((i) = 0, (pipes) = (first_pipes) | ((second_pipes) << 4); \
>               (i) < 8 && ((crtc) = intel_crtc_for_pipe((i & 3)), 1); \

We could probably use a single internal define for the magic
number to avoid things going out of sync by accident.

Hmm, maybe even define it as something like
#define _INTEL_MAX_PIPES_POT roundup_power_of_two(I915_MAX_PIPES)
?

O, I suppose we don't really need it to be POT, so we could
just replace the '&' with '%', and then we can just use
I915_MAX_PIPES directly.

>               (i)++) \
>                  for_each_if((crtc) && (pipes) & BIT(i))
> 
> #define for_each_crtc_in_masks_reverse(crtc, first_pipes, second_pipes, 
> pipes, i) \
>          for ((i) = 7, (pipes) = (first_pipes) | ((second_pipes) << 4); \
>               (i) >= 0 && ((crtc) = intel_crtc_for_pipe((i & 3)), 1); \
>               (i)--) \
>                  for_each_if((crtc) && (pipes) & BIT(i))
> 
> But, for non joiner case, when the bigjoiner_primary/secondary_pipes are 
> 0 so pipes will be 0.

Hmm. I think we just need to make bigjoiner_primary_pipes()
return BIT(crtc->pipe) for the non-joiner cases.

Maybe we should rename these to something like
_modeset_{primary,secondary}_pipes() so that people
don't get tempted to use them for anything else?

And then we could hide all this into something like
#define for_each_pipe_crtc_modeset_disable(...) \ 
	for_each_crtc_in_masks(..., _modeset_primary_pipes(), \
			       _modeset_secondary_pipes(), ...)
#define for_each_pipe_crtc_modeset_enable(...) \ 
	for_each_crtc_in_masks_reverse(..., _modeset_secondary_pipes(), \
				      _modeset_primary_pipes(), ...)

-- 
Ville Syrjälä
Intel