[Intel-gfx] [PATCH v3 3/3] drm/i915/display/fbc: Make fences a nice-to-have for GEN9+
Souza, Jose
jose.souza at intel.com
Thu Mar 19 21:12:15 UTC 2020
On Wed, 2020-03-18 at 14:44 +0200, Ville Syrjälä wrote:
> On Thu, Mar 12, 2020 at 12:35:56AM +0000, Souza, Jose wrote:
> > On Thu, 2020-03-05 at 17:33 -0800, José Roberto de Souza wrote:
> > > On Thu, 2020-02-20 at 19:26 +0200, Ville Syrjälä wrote:
> > > > On Tue, Feb 18, 2020 at 05:42:30PM -0800, José Roberto de Souza
> > > > wrote:
> > > > > dGFX have local memory so it do not have aperture and do not
> > > > > support
> > > > > CPU fences but even for iGFX it have a small number of
> > > > > fences.
> > > > >
> > > > > As replacement for fences to track frontbuffer modifications
> > > > > by
> > > > > CPU
> > > > > we have a software tracking that is already in used by FBC
> > > > > and
> > > > > PSR.
> > > > > PSR don't support fences so it shows that this tracking is
> > > > > reliable.
> > > > >
> > > > > So lets make fences a nice-to-have to activate FBC for GEN9+,
> > > > > this
> > > > > will allow us to enable FBC for dGFXs and iGFXs even when
> > > > > there
> > > > > is
> > > > > no
> > > > > available fence.
> > > > >
> > > > > We do not set fences to rotated planes but FBC only have
> > > > > restrictions
> > > > > against 16bpp, so adding it here.
> > > > >
> > > > > Also adding a new check for the tiling format, fences are
> > > > > only
> > > > > set
> > > > > to X and Y tiled planes but again FBC don't have any
> > > > > restrictions
> > > > > against tiling so adding linear as supported as well, other
> > > > > formats
> > > > > should be added after tested but IGT only supports drawing in
> > > > > thse
> > > > > 3 formats.
> > > > >
> > > > > intel_fbc_hw_tracking_covers_screen() maybe can also have the
> > > > > same
> > > > > treatment as fences but BSpec is not clear if the size
> > > > > limitation
> > > > > is
> > > > > for hardware tracking or general use of FBC and I don't have
> > > > > a 5K
> > > > > display to test it, so keeping as is for safety.
> > > > >
> > > > > v2:
> > > > > - Added tiling and pixel format rotation checks
> > > > > - Changed the GEN version not requiring fences to 11 from 9,
> > > > > DDX
> > > > > needs some changes but it don't have support for GEN11+
> > > > >
> > > > > v3:
> > > > > - Changed back to GEN9+
> > > > > - Moved GEN test to inside of tiling_is_valid()
> > > > >
> > > > > Cc: Daniel Vetter <daniel.vetter at intel.com>
> > > > > Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com>
> > > > > Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> > > > > Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> > > > > ---
> > > > > drivers/gpu/drm/i915/display/intel_fbc.c | 45
> > > > > ++++++++++++++++++++----
> > > > > drivers/gpu/drm/i915/i915_drv.h | 1 +
> > > > > 2 files changed, 39 insertions(+), 7 deletions(-)
> > > > >
> > > > > diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c
> > > > > b/drivers/gpu/drm/i915/display/intel_fbc.c
> > > > > index 1d76e3646a25..a0d1d661a006 100644
> > > > > --- a/drivers/gpu/drm/i915/display/intel_fbc.c
> > > > > +++ b/drivers/gpu/drm/i915/display/intel_fbc.c
> > > > > @@ -585,7 +585,7 @@ static bool stride_is_valid(struct
> > > > > drm_i915_private *dev_priv,
> > > > > }
> > > > >
> > > > > static bool pixel_format_is_valid(struct drm_i915_private
> > > > > *dev_priv,
> > > > > - u32 pixel_format)
> > > > > + u32 pixel_format, unsigned
> > > > > int
> > > > > rotation)
> > > > > {
> > > > > switch (pixel_format) {
> > > > > case DRM_FORMAT_XRGB8888:
> > > > > @@ -599,6 +599,9 @@ static bool pixel_format_is_valid(struct
> > > > > drm_i915_private *dev_priv,
> > > > > /* WaFbcOnly1to1Ratio:ctg */
> > > > > if (IS_G4X(dev_priv))
> > > > > return false;
> > > > > + if ((rotation & (DRM_MODE_ROTATE_90 |
> > > > > DRM_MODE_ROTATE_270)) &&
> > > > > + INTEL_GEN(dev_priv) >= 9)
> > > > > + return false;
> > > >
> > > > Would still would prefer a rotations_is_valid() or some such
> > > > thing.
> > >
> > > Like this?
> > >
> > > diff --git a/drivers/gpu/drm/i915/display/intel_fbc.c
> > > b/drivers/gpu/drm/i915/display/intel_fbc.c
> > > index 5e35c894bdf9..692edd45b769 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_fbc.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_fbc.c
> > > @@ -600,15 +600,21 @@ static bool pixel_format_is_valid(struct
> > > drm_i915_private *dev_priv,
> > > /* WaFbcOnly1to1Ratio:ctg */
> > > if (IS_G4X(dev_priv))
> > > return false;
> > > - if ((rotation & (DRM_MODE_ROTATE_90 |
> > > DRM_MODE_ROTATE_270)) &&
> > > - INTEL_GEN(dev_priv) >= 9)
> > > - return false;
> > > return true;
> > > default:
> > > return false;
> > > }
> > > }
> > >
> > > +static bool rotations_is_valid(struct drm_i915_private
> > > *dev_priv,
> > > + u32 pixel_format, unsigned int
> > > rotation)
> > > +{
> > > + if (INTEL_GEN(dev_priv) >= 9 && pixel_format ==
> > > DRM_FORMAT_RGB565 &&
> > > + rotation & (DRM_MODE_ROTATE_90 |
> > > DRM_MODE_ROTATE_270))
> > > + return false;
> > > + return true;
> > > +}
> > > +
> > > /*
> > > * For some reason, the hardware tracking starts looking at
> > > whatever
> > > we
> > > * programmed as the display plane base address register. It
> > > does
> > > not
> > > look at
> > > @@ -810,6 +816,12 @@ static bool intel_fbc_can_activate(struct
> > > intel_crtc *crtc)
> > > return false;
> > > }
> > >
> > > + if (!rotations_is_valid(dev_priv, cache->fb.format-
> > > >format,
> > > + cache->plane.rotation)) {
> > > + fbc->no_fbc_reason = "plane rotation is invalid";
> > > + return false;
> > > + }
> > > +
> > > if (cache->plane.pixel_blend_mode !=
> > > DRM_MODE_BLEND_PIXEL_NONE
> > > &&
> > > cache->fb.format->has_alpha) {
> > > fbc->no_fbc_reason = "per-pixel alpha blending is
> > > incompatible with FBC";
> > >
> > >
> > > > > return true;
> > > > > default:
> > > > > return false;
> > > > > @@ -639,6 +642,22 @@ static bool
> > > > > intel_fbc_hw_tracking_covers_screen(struct intel_crtc *crtc)
> > > > > return effective_w <= max_w && effective_h <= max_h;
> > > > > }
> > > > >
> > > > > +static bool tiling_is_valid(struct drm_i915_private
> > > > > *dev_priv,
> > > > > + uint64_t modifier)
> > > > > +{
> > > > > + switch (modifier) {
> > > > > + case DRM_FORMAT_MOD_LINEAR:
> > > > > + if (INTEL_GEN(dev_priv) >= 9)
> > > > > + return true;
> > > >
> > > > Have we checked that eg. fbcon cursor still blinks correctly
> > > > with FBC active and all?
> > >
> > > Hum on fbcon FBC is enabled but it never compress, IGT tests with
> > > fences complete disables are working fine, screen is updated when
> > > tests
> > > asks to with FBC enabled and compressing.
> > >
> > > I will debug fbcon a little more to understand why it is never
> > > compressing.
> >
> > Actually is is compressing but is very rare, I even reduced the
> > blink
> > rate to 1hz but it did not helped.
>
> Is FBC actually enabled all the time though? By "compressing" I take
> you mean the debugfs thing we have? I don't actually remember what
> that looks at. Number of compressed segments? Or something else?
Exacly that.
> You're polling it fast enough to not simply suffer from poor
> sampling?
Hum in other platforms the compressing is more consistent.
>
> > I have compared the plane registers
> > between fbcon and IGT both in tiling linear but the only difference
> > is
> > the plane surface address:
> >
> > # fbcon
> > [drm:skl_update_plane [i915]] skl_program_plane() pipeA plane=A
> > [drm:skl_update_plane [i915]] plane_stride=78
> > [drm:skl_update_plane [i915]] plane_pos=0
> > [drm:skl_update_plane [i915]] plane_size=437077f
> > [drm:skl_update_plane [i915]] plane_aux_dist=0
> > [drm:skl_update_plane [i915]] plane_color_ctl=2000
> > [drm:skl_update_plane [i915]] plane_keyval=0
> > [drm:skl_update_plane [i915]] plane_keymsk=0
> > [drm:skl_update_plane [i915]] plane_keymax=ff000000
> > [drm:skl_update_plane [i915]] plane_offset=0
> > [drm:skl_update_plane [i915]] plane_ctl=84000000
> > [drm:skl_update_plane [i915]] plane_surf=40000
> >
> > # IGT test with tiling linear framebuffer
> > [drm:skl_update_plane [i915]] skl_program_plane() pipeA plane=A
> > [drm:skl_update_plane [i915]] plane_stride=78
> > [drm:skl_update_plane [i915]] plane_pos=0
> > [drm:skl_update_plane [i915]] plane_size=437077f
> > [drm:skl_update_plane [i915]] plane_aux_dist=0
> > [drm:skl_update_plane [i915]] plane_color_ctl=2000
> > [drm:skl_update_plane [i915]] plane_keyval=0
> > [drm:skl_update_plane [i915]] plane_keymsk=0
> > [drm:skl_update_plane [i915]] plane_keymax=ff000000
> > [drm:skl_update_plane [i915]] plane_offset=0
> > [drm:skl_update_plane [i915]] plane_ctl=84000000
> > [drm:skl_update_plane [i915]] plane_surf=1040000
> >
> > Do you have any tips of what could be causing this?
> >
> > > > > + return false;
> > > > > + case I915_FORMAT_MOD_X_TILED:
> > > > > + case I915_FORMAT_MOD_Y_TILED:
> > > > > + return true;
> > > > > + default:
> > > > > + return false;
> > > > > + }
> > > > > +}
> > > > > +
> > > > > static void intel_fbc_update_state_cache(struct intel_crtc
> > > > > *crtc,
> > > > > const struct
> > > > > intel_crtc_state
> > > > > *crtc_state,
> > > > > const struct
> > > > > intel_plane_state
> > > > > *plane_state)
> > > > > @@ -672,6 +691,7 @@ static void
> > > > > intel_fbc_update_state_cache(struct
> > > > > intel_crtc *crtc,
> > > > >
> > > > > cache->fb.format = fb->format;
> > > > > cache->fb.stride = fb->pitches[0];
> > > > > + cache->fb.modifier = fb->modifier;
> > > > >
> > > > > drm_WARN_ON(&dev_priv->drm, plane_state->flags &
> > > > > PLANE_HAS_FENCE &&
> > > > > !plane_state->vma->fence);
> > > > > @@ -720,23 +740,33 @@ static bool
> > > > > intel_fbc_can_activate(struct
> > > > > intel_crtc *crtc)
> > > > > return false;
> > > > > }
> > > > >
> > > > > - /* The use of a CPU fence is mandatory in order to
> > > > > detect
> > > > > writes
> > > > > - * by the CPU to the scanout and trigger updates to the
> > > > > FBC.
> > > > > + /* The use of a CPU fence is one of two ways to detect
> > > > > writes
> > > > > by the
> > > > > + * CPU to the scanout and trigger updates to the FBC.
> > > > > + *
> > > > > + * The other method is by software tracking(see
> > > > > + * intel_fbc_invalidate/flush()), it will manually
> > > > > notify FBC
> > > > > and nuke
> > > > > + * the current compressed buffer and recompress it.
> > > > > *
> > > > > * Note that is possible for a tiled surface to be
> > > > > unmappable
> > > > > (and
> > > > > - * so have no fence associated with it) due to aperture
> > > > > constaints
> > > > > + * so have no fence associated with it) due to aperture
> > > > > constraints
> > > > > * at the time of pinning.
> > > > > *
> > > > > * FIXME with 90/270 degree rotation we should use the
> > > > > fence on
> > > > > * the normal GTT view (the rotated view doesn't even
> > > > > have a
> > > > > * fence). Would need changes to the FBC fence Y offset
> > > > > as
> > > > > well.
> > > > > - * For now this will effecively disable FBC with 90/270
> > > > > degree
> > > > > + * For now this will effectively disable FBC with
> > > > > 90/270 degree
> > > > > * rotation.
> > > > > */
> > > > > - if (cache->fence_id < 0) {
> > > > > + if (INTEL_GEN(dev_priv) < 9 && cache->fence_id < 0) {
> > > > > fbc->no_fbc_reason = "framebuffer not tiled or
> > > > > fenced";
> > > > > return false;
> > > > > }
> > > > > +
> > > > > + if (!tiling_is_valid(dev_priv, cache->fb.modifier)) {
> > > > > + fbc->no_fbc_reason = "tiling unsupported";
> > > > > + return false;
> > > > > + }
> > > > > +
> > > > > if (INTEL_GEN(dev_priv) <= 4 && !IS_G4X(dev_priv) &&
> > > > > cache->plane.rotation != DRM_MODE_ROTATE_0) {
> > > > > fbc->no_fbc_reason = "rotation unsupported";
> > > > > @@ -748,7 +778,8 @@ static bool intel_fbc_can_activate(struct
> > > > > intel_crtc *crtc)
> > > > > return false;
> > > > > }
> > > > >
> > > > > - if (!pixel_format_is_valid(dev_priv, cache->fb.format-
> > > > > > format))
> > > > > {
> > > > > + if (!pixel_format_is_valid(dev_priv, cache->fb.format-
> > > > > >format,
> > > > > + cache->plane.rotation)) {
> > > > > fbc->no_fbc_reason = "pixel format is invalid";
> > > > > return false;
> > > > > }
> > > > > diff --git a/drivers/gpu/drm/i915/i915_drv.h
> > > > > b/drivers/gpu/drm/i915/i915_drv.h
> > > > > index 3330b538d379..bf88663d8217 100644
> > > > > --- a/drivers/gpu/drm/i915/i915_drv.h
> > > > > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > > > > @@ -413,6 +413,7 @@ struct intel_fbc {
> > > > > struct {
> > > > > const struct drm_format_info *format;
> > > > > unsigned int stride;
> > > > > + u64 modifier;
> > > > > } fb;
> > > > > u16 gen9_wa_cfb_stride;
> > > > > s8 fence_id;
> > > > > --
> > > > > 2.25.1
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