[Intel-gfx] [PATCH v2] drm/i915: Use intel_plane_data_rate for min_cdclk calculation
Ville Syrjälä
ville.syrjala at linux.intel.com
Fri Feb 21 15:02:57 UTC 2020
On Fri, Feb 21, 2020 at 02:38:01PM +0000, Lisovskiy, Stanislav wrote:
> On Fri, 2020-02-21 at 16:04 +0200, Ville Syrjälä wrote:
> > On Thu, Feb 20, 2020 at 06:08:56PM +0200, Stanislav Lisovskiy wrote:
> > > There seems to be a bit of confusing redundancy in a way, how
> > > plane data rate/min cdclk are calculated.
> > > In fact both min cdclk, pixel rate and plane data rate are all
> > > part of the same formula as per BSpec.
> > >
> > > However currently we have intel_plane_data_rate, which is used
> > > to calculate plane data rate and which is also used in bandwidth
> > > calculations. However for calculating min_cdclk we have another
> > > piece of code, doing almost same calculation, but a bit differently
> > > and in a different place. However as both are actually part of same
> > > formula, probably would be wise to use plane data rate calculations
> > > as a basis anyway, thus avoiding code duplication and possible bugs
> > > related to this.
> > >
> > > Another thing is that I've noticed that during min_cdclk
> > > calculations
> > > we account for plane scaling, while for plane data rate, we don't.
> > > crtc->pixel_rate seems to account only for pipe ratio, however it
> > > is
> > > clearly stated in BSpec that plane data rate also need to account
> > > plane ratio as well.
> > >
> > > So what this commit does is:
> > > - Adds a plane ratio calculation to intel_plane_data_rate
> > > - Removes redundant calculations from skl_plane_min_cdclk which is
> > > used for gen9+ and now uses intel_plane_data_rate as a basis from
> > > there as well.
> > >
> > > v2: - Don't use 64 division if not needed(Ville Syrjälä)
> > > - Now use intel_plane_pixel_rate as a basis for calculations
> > > both
> > > at intel_plane_data_rate and skl_plane_min_cdclk(Ville
> > > Syrjälä)
> > >
> > > Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
> > > ---
> > > .../gpu/drm/i915/display/intel_atomic_plane.c | 22
> > > +++++++++++++++-
> > > .../gpu/drm/i915/display/intel_atomic_plane.h | 3 +++
> > > drivers/gpu/drm/i915/display/intel_sprite.c | 26 +++++++------
> > > ------
> > > 3 files changed, 33 insertions(+), 18 deletions(-)
> > >
> > > diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> > > b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> > > index c86d7a35c816..3bd7ea9bf1b4 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.c
> > > @@ -133,11 +133,31 @@ intel_plane_destroy_state(struct drm_plane
> > > *plane,
> > > kfree(plane_state);
> > > }
> > >
> > > +unsigned int intel_plane_pixel_rate(const struct intel_crtc_state
> > > *crtc_state,
> > > + const struct intel_plane_state
> > > *plane_state)
> > > +{
> > > + unsigned int src_w, src_h, dst_w, dst_h;
> > > +
> > > + src_w = drm_rect_width(&plane_state->uapi.src) >> 16;
> > > + src_h = drm_rect_height(&plane_state->uapi.src) >> 16;
> > > + dst_w = drm_rect_width(&plane_state->uapi.dst);
> > > + dst_h = drm_rect_height(&plane_state->uapi.dst);
> > > +
> > > + /* Downscaling limits the maximum pixel rate */
> > > + dst_w = min(src_w, dst_w);
> > > + dst_h = min(src_h, dst_h);
> > > +
> > > + return DIV_ROUND_UP(mul_u32_u32(crtc_state->pixel_rate,
> >
> > Wrong macro for 64/32->32 division.
>
> Yes, in fact we should use 64 macro here still.
> As I understand pixel rate is stored in kHz so for instance
> for pixel rate 172800 * 4K * 4K we already overflowing u32.
> Was just a bit confused with prev comment :)
>
> >
> > > + src_w * src_h),
> > > + mul_u32_u32(dst_w, dst_h));
> >
> > And the divisor shouldn't be a u64.
>
> Agree divisor is not, however divident is 64.
> >
> > > +}
> > > +
> > > unsigned int intel_plane_data_rate(const struct intel_crtc_state
> > > *crtc_state,
> > > const struct intel_plane_state
> > > *plane_state)
> > > {
> > > const struct drm_framebuffer *fb = plane_state->hw.fb;
> > > unsigned int cpp;
> > > + unsigned int plane_pixel_rate =
> > > intel_plane_pixel_rate(crtc_state, plane_state);
> >
> > Just 'pixel_rate' should do. We know the rest from the fact that this
> > is a plane function. Also I'd put this first so the declaration block
> > looks at least a bit less messy.
> >
> > >
> > > if (!plane_state->uapi.visible)
> > > return 0;
> > > @@ -153,7 +173,7 @@ unsigned int intel_plane_data_rate(const struct
> > > intel_crtc_state *crtc_state,
> > > if (fb->format->is_yuv && fb->format->num_planes > 1)
> > > cpp *= 4;
> > >
> > > - return cpp * crtc_state->pixel_rate;
> > > + return mul_u32_u32(plane_pixel_rate, cpp);
> >
> > We're not returning a u64.
> >
> > > }
> > >
> > > int intel_plane_calc_min_cdclk(struct intel_atomic_state *state,
> > > diff --git a/drivers/gpu/drm/i915/display/intel_atomic_plane.h
> > > b/drivers/gpu/drm/i915/display/intel_atomic_plane.h
> > > index 2bcf15e34728..a6bbf42bae1f 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_atomic_plane.h
> > > +++ b/drivers/gpu/drm/i915/display/intel_atomic_plane.h
> > > @@ -18,6 +18,9 @@ struct intel_plane_state;
> > >
> > > extern const struct drm_plane_helper_funcs
> > > intel_plane_helper_funcs;
> > >
> > > +unsigned int intel_plane_pixel_rate(const struct intel_crtc_state
> > > *crtc_state,
> > > + const struct intel_plane_state
> > > *plane_state);
> > > +
> > > unsigned int intel_plane_data_rate(const struct intel_crtc_state
> > > *crtc_state,
> > > const struct intel_plane_state
> > > *plane_state);
> > > void intel_plane_copy_uapi_to_hw_state(struct intel_plane_state
> > > *plane_state,
> > > diff --git a/drivers/gpu/drm/i915/display/intel_sprite.c
> > > b/drivers/gpu/drm/i915/display/intel_sprite.c
> > > index 7abeefe8dce5..4fa3081e2074 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_sprite.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_sprite.c
> > > @@ -330,9 +330,9 @@ bool icl_is_hdr_plane(struct drm_i915_private
> > > *dev_priv, enum plane_id plane_id)
> > > }
> > >
> > > static void
> > > -skl_plane_ratio(const struct intel_crtc_state *crtc_state,
> > > - const struct intel_plane_state *plane_state,
> > > - unsigned int *num, unsigned int *den)
> > > +skl_plane_bpp_constraints(const struct intel_crtc_state
> > > *crtc_state,
> > > + const struct intel_plane_state *plane_state,
> > > + unsigned int *num, unsigned int *den)
> >
> > Bogus rename.
>
> Well, I guess you agree, that this function is not returning
> plane_ratio either :) Was just wondering if it has to be named somewhat
> differently.
It returns the plane ratio excluding the downscaling component.
So seems good enough to me. Or at least I can't immediately
think of anything particularly better.
--
Ville Syrjälä
Intel
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