diff options
| author | Ville Syrjälä <ville.syrjala@linux.intel.com> | 2023-03-11 01:58:26 +0200 |
|---|---|---|
| committer | Ville Syrjälä <ville.syrjala@linux.intel.com> | 2023-03-18 14:24:51 +0200 |
| commit | 6e8acb6686d805ac5d127fb691e28e742248c523 (patch) | |
| tree | 36c82fbb2942a5a96810e7854c8afcb7113384f1 /drivers/gpu/drm/i915/display/intel_display.c | |
| parent | 8cb1f95cca68421b08333175719fdd3615372ca8 (diff) | |
drm/i915: Add belts and suspenders locking for seamless M/N changes
Add some (probably overkill) locking to protect the vblank
timestamping constants updates during seamless M/N fastsets.
As everything should be naturally aligned I think the individual
pieces should probably end up updating atomically enough. So this
is only really meant to guarantee everyone sees a consistent whole.
All the drm_vblank.c usage is covered by vblank_time_lock,
and uncore.lock will take care of __intel_get_crtc_scanline()
that can also be called from outside the core vblank functionality.
Currently only crtc_clock and framedur_ns can change, but in
the future might fastset also across eg. vtotal/vblank_end
changes, so let's just grab the locks across the whole thing.
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230310235828.17439-2-ville.syrjala@linux.intel.com
Diffstat (limited to 'drivers/gpu/drm/i915/display/intel_display.c')
| -rw-r--r-- | drivers/gpu/drm/i915/display/intel_display.c | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c index 7305ad6592d3..4fd64dcfaf12 100644 --- a/drivers/gpu/drm/i915/display/intel_display.c +++ b/drivers/gpu/drm/i915/display/intel_display.c @@ -5907,6 +5907,8 @@ void intel_crtc_update_active_timings(const 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); struct drm_display_mode adjusted_mode; + int vmax_vblank_start = 0; + unsigned long irqflags; drm_mode_init(&adjusted_mode, &crtc_state->hw.adjusted_mode); @@ -5914,11 +5916,28 @@ void intel_crtc_update_active_timings(const struct intel_crtc_state *crtc_state) adjusted_mode.crtc_vtotal = crtc_state->vrr.vmax; adjusted_mode.crtc_vblank_end = crtc_state->vrr.vmax; adjusted_mode.crtc_vblank_start = intel_vrr_vmin_vblank_start(crtc_state); - crtc->vmax_vblank_start = intel_vrr_vmax_vblank_start(crtc_state); + vmax_vblank_start = intel_vrr_vmax_vblank_start(crtc_state); } + /* + * Belts and suspenders locking to guarantee everyone sees 100% + * consistent state during fastset seamless refresh rate changes. + * + * vblank_time_lock takes care of all drm_vblank.c stuff, and + * uncore.lock takes care of __intel_get_crtc_scanline() which + * may get called elsewhere as well. + * + * TODO maybe just protect everything (including + * __intel_get_crtc_scanline()) with vblank_time_lock? + * Need to audit everything to make sure it's safe. + */ + spin_lock_irqsave(&dev_priv->drm.vblank_time_lock, irqflags); + spin_lock(&dev_priv->uncore.lock); + drm_calc_timestamping_constants(&crtc->base, &adjusted_mode); + crtc->vmax_vblank_start = vmax_vblank_start; + crtc->mode_flags = crtc_state->mode_flags; /* @@ -5962,6 +5981,9 @@ void intel_crtc_update_active_timings(const struct intel_crtc_state *crtc_state) } else { crtc->scanline_offset = 1; } + + spin_unlock(&dev_priv->uncore.lock); + spin_unlock_irqrestore(&dev_priv->drm.vblank_time_lock, irqflags); } /* |