[Intel-gfx] [PATCH 1/2] drm/i915: Do not rely on wm preservation for ILK watermarks
Matt Roper
matthew.d.roper at intel.com
Fri Oct 27 01:09:38 UTC 2017
On Wed, Oct 25, 2017 at 08:03:47AM +0200, Maarten Lankhorst wrote:
> Op 25-10-17 om 01:01 schreef Matt Roper:
> > On Thu, Oct 19, 2017 at 05:13:40PM +0200, Maarten Lankhorst wrote:
> >> The original intent was to preserve watermarks as much as possible
> >> in intel_pipe_wm.raw_wm, and put the validated ones in intel_pipe_wm.wm.
> >>
> >> It seems this approach is insufficient and we don't always preserve
> >> the raw watermarks, so just use the atomic iterator we're already using
> >> to get a const pointer to all bound planes on the crtc.
> >>
> >> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=102373
> >> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> >> Cc: stable at vger.kernel.org #v4.8+
> > It's been a while since I looked at this code, so I'm not sure I'm
> > following all the context/history here. Before this patch, we had
> > calculated watermarks for all levels (even those above the maximum
> > usable watermark level as determined by sprite usage) into raw_wm. But
> > as far as I can tell, we never actually used those values for anything
> > so that was no different than just throwing the values away?
>
> No, the trick introduced there was that we preserved the raw watermarks for future
> calculations to not include all planes in a commit. This is now solved by using the
> read-only drm_atomic_crtc_state_for_each_plane_state iterator, to get all
> const plane states without having to include them.
>
> > Is my understanding correct that this is mostly a revert of 71f0a62614
> > ("drm/i915: Only use sanitized values for ILK watermarks) except that it
> > also modifies the level validation loop so that we're only calling
> > ilk_compute_wm_level() on the levels up to usable_level whereas before
> > that patch we were calling it on all levels, but then
> > setting wm->enable = false for the unusable levels?
> >
> > By my understanding, this looks like a safe simplification of the
> > current logic, but I don't see where the functional change is here.
> > Was the Buzilla: reference supposed to be tied to patch #2 of this
> > series or am I missing something important?
>
> We now throw away all watermarks, and use drm_atomic_crtc_state_for_each_plane_state
> to get the plane states. As a result we can throw away the raw watermarks, which have
> proven to be insufficiently preserved. :)
Okay, makes more sense now. Thanks for clarifying.
Reviewed-by: Matt Roper <matthew.d.roper at intel.com>
>
> >> ---
> >> drivers/gpu/drm/i915/intel_drv.h | 1 -
> >> drivers/gpu/drm/i915/intel_pm.c | 51 +++++++++++++++++-----------------------
> >> 2 files changed, 21 insertions(+), 31 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> >> index 47d022d48718..7bc60c848940 100644
> >> --- a/drivers/gpu/drm/i915/intel_drv.h
> >> +++ b/drivers/gpu/drm/i915/intel_drv.h
> >> @@ -499,7 +499,6 @@ struct intel_crtc_scaler_state {
> >>
> >> struct intel_pipe_wm {
> >> struct intel_wm_level wm[5];
> >> - struct intel_wm_level raw_wm[5];
> >> uint32_t linetime;
> >> bool fbc_wm_enabled;
> >> bool pipe_enabled;
> >> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> >> index c42a65a93b3a..ea70c720f492 100644
> >> --- a/drivers/gpu/drm/i915/intel_pm.c
> >> +++ b/drivers/gpu/drm/i915/intel_pm.c
> >> @@ -2721,9 +2721,9 @@ static void ilk_compute_wm_level(const struct drm_i915_private *dev_priv,
> >> const struct intel_crtc *intel_crtc,
> >> int level,
> >> struct intel_crtc_state *cstate,
> >> - struct intel_plane_state *pristate,
> >> - struct intel_plane_state *sprstate,
> >> - struct intel_plane_state *curstate,
> >> + const struct intel_plane_state *pristate,
> >> + const struct intel_plane_state *sprstate,
> >> + const struct intel_plane_state *curstate,
> >> struct intel_wm_level *result)
> >> {
> >> uint16_t pri_latency = dev_priv->wm.pri_latency[level];
> >> @@ -3043,28 +3043,24 @@ static int ilk_compute_pipe_wm(struct intel_crtc_state *cstate)
> >> struct intel_pipe_wm *pipe_wm;
> >> struct drm_device *dev = state->dev;
> >> const struct drm_i915_private *dev_priv = to_i915(dev);
> >> - struct intel_plane *intel_plane;
> >> - struct intel_plane_state *pristate = NULL;
> >> - struct intel_plane_state *sprstate = NULL;
> >> - struct intel_plane_state *curstate = NULL;
> >> + struct drm_plane *plane;
> >> + const struct drm_plane_state *plane_state;
> >> + const struct intel_plane_state *pristate = NULL;
> >> + const struct intel_plane_state *sprstate = NULL;
> >> + const struct intel_plane_state *curstate = NULL;
> >> int level, max_level = ilk_wm_max_level(dev_priv), usable_level;
> >> struct ilk_wm_maximums max;
> >>
> >> pipe_wm = &cstate->wm.ilk.optimal;
> >>
> >> - for_each_intel_plane_on_crtc(dev, intel_crtc, intel_plane) {
> >> - struct intel_plane_state *ps;
> >> -
> >> - ps = intel_atomic_get_existing_plane_state(state,
> >> - intel_plane);
> >> - if (!ps)
> >> - continue;
> >> + drm_atomic_crtc_state_for_each_plane_state(plane, plane_state, &cstate->base) {
> >> + const struct intel_plane_state *ps = to_intel_plane_state(plane_state);
> >>
> >> - if (intel_plane->base.type == DRM_PLANE_TYPE_PRIMARY)
> >> + if (plane->type == DRM_PLANE_TYPE_PRIMARY)
> >> pristate = ps;
> >> - else if (intel_plane->base.type == DRM_PLANE_TYPE_OVERLAY)
> >> + else if (plane->type == DRM_PLANE_TYPE_OVERLAY)
> >> sprstate = ps;
> >> - else if (intel_plane->base.type == DRM_PLANE_TYPE_CURSOR)
> >> + else if (plane->type == DRM_PLANE_TYPE_CURSOR)
> >> curstate = ps;
> >> }
> >>
> >> @@ -3086,11 +3082,9 @@ static int ilk_compute_pipe_wm(struct intel_crtc_state *cstate)
> >> if (pipe_wm->sprites_scaled)
> >> usable_level = 0;
> >>
> >> - ilk_compute_wm_level(dev_priv, intel_crtc, 0, cstate,
> >> - pristate, sprstate, curstate, &pipe_wm->raw_wm[0]);
> >> -
> >> memset(&pipe_wm->wm, 0, sizeof(pipe_wm->wm));
> >> - pipe_wm->wm[0] = pipe_wm->raw_wm[0];
> >> + ilk_compute_wm_level(dev_priv, intel_crtc, 0, cstate,
> >> + pristate, sprstate, curstate, &pipe_wm->wm[0]);
> >>
> >> if (IS_HASWELL(dev_priv) || IS_BROADWELL(dev_priv))
> >> pipe_wm->linetime = hsw_compute_linetime_wm(cstate);
> >> @@ -3100,8 +3094,8 @@ static int ilk_compute_pipe_wm(struct intel_crtc_state *cstate)
> >>
> >> ilk_compute_wm_reg_maximums(dev_priv, 1, &max);
> >>
> >> - for (level = 1; level <= max_level; level++) {
> >> - struct intel_wm_level *wm = &pipe_wm->raw_wm[level];
> >> + for (level = 1; level <= usable_level; level++) {
> >> + struct intel_wm_level *wm = &pipe_wm->wm[level];
> >>
> >> ilk_compute_wm_level(dev_priv, intel_crtc, level, cstate,
> >> pristate, sprstate, curstate, wm);
> >> @@ -3111,13 +3105,10 @@ static int ilk_compute_pipe_wm(struct intel_crtc_state *cstate)
> >> * register maximums since such watermarks are
> >> * always invalid.
> >> */
> >> - if (level > usable_level)
> >> - continue;
> >> -
> >> - if (ilk_validate_wm_level(level, &max, wm))
> >> - pipe_wm->wm[level] = *wm;
> >> - else
> >> - usable_level = level;
> >> + if (!ilk_validate_wm_level(level, &max, wm)) {
> >> + memset(wm, 0, sizeof(*wm));
> >> + break;
> >> + }
> >> }
> >>
> >> return 0;
> >> --
> >> 2.14.1
> >>
> >> _______________________________________________
> >> Intel-gfx mailing list
> >> Intel-gfx at lists.freedesktop.org
> >> https://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
>
--
Matt Roper
Graphics Software Engineer
IoTG Platform Enabling & Development
Intel Corporation
(916) 356-2795
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