On Tue, 11 Jun 2024, Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx> wrote: > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > As we extend the use of DSB for critical pipe/plane register > programming, it'll be nice to have an escape valve at hand, > in case things go very poorly. To that end, add a i915.enable_dsb > modparam by which we can force the driver to take the pure mmio > path instead. > > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > --- > drivers/gpu/drm/i915/display/intel_display_params.c | 3 +++ > drivers/gpu/drm/i915/display/intel_display_params.h | 1 + > drivers/gpu/drm/i915/display/intel_dsb.c | 3 +++ > 3 files changed, 7 insertions(+) > > diff --git a/drivers/gpu/drm/i915/display/intel_display_params.c b/drivers/gpu/drm/i915/display/intel_display_params.c > index aebdb7b59dbf..449a31767791 100644 > --- a/drivers/gpu/drm/i915/display/intel_display_params.c > +++ b/drivers/gpu/drm/i915/display/intel_display_params.c > @@ -54,6 +54,9 @@ intel_display_param_named_unsafe(enable_dc, int, 0400, > intel_display_param_named_unsafe(enable_dpt, bool, 0400, > "Enable display page table (DPT) (default: true)"); > > +intel_display_param_named_unsafe(enable_dsb, bool, 0600, > + "Enable display state buffer (DSB) (default: true)"); Not much point in leaving the module param 0600, is there? BR, Jani. > + > intel_display_param_named_unsafe(enable_sagv, bool, 0400, > "Enable system agent voltage/frequency scaling (SAGV) (default: true)"); > > diff --git a/drivers/gpu/drm/i915/display/intel_display_params.h b/drivers/gpu/drm/i915/display/intel_display_params.h > index 1208a62c16d2..48c29c55c939 100644 > --- a/drivers/gpu/drm/i915/display/intel_display_params.h > +++ b/drivers/gpu/drm/i915/display/intel_display_params.h > @@ -31,6 +31,7 @@ struct drm_i915_private; > param(int, vbt_sdvo_panel_type, -1, 0400) \ > param(int, enable_dc, -1, 0400) \ > param(bool, enable_dpt, true, 0400) \ > + param(bool, enable_dsb, true, 0600) \ > param(bool, enable_sagv, true, 0600) \ > param(int, disable_power_well, -1, 0400) \ > param(bool, enable_ips, true, 0600) \ > diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c > index bee48ac419ce..2ab3765f6c06 100644 > --- a/drivers/gpu/drm/i915/display/intel_dsb.c > +++ b/drivers/gpu/drm/i915/display/intel_dsb.c > @@ -460,6 +460,9 @@ struct intel_dsb *intel_dsb_prepare(struct intel_atomic_state *state, > if (!HAS_DSB(i915)) > return NULL; > > + if (!i915->display.params.enable_dsb) > + return NULL; > + > /* TODO: DSB is broken in Xe KMD, so disabling it until fixed */ > if (!IS_ENABLED(I915)) > return NULL; -- Jani Nikula, Intel
