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)"); + 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; -- 2.44.2
