Re: [PATCH] drm/i915: Disable DSB in Xe KMD

[Jani Nikula <jani.nikula@linux.intel.com>]

On Wed, 03 Jan 2024, José Roberto de Souza <jose.souza@intel.com> wrote:
> Often getting DBS overflows when starting Xorg or Wayland compositor
> when running Xe KMD.
> Issue was reported but nothing was done, so disabling DSB as whole
> until properly fixed.

Please just incorporate this into the HAS_DSB() check, and don't litter
the source with ifdefs.

Thanks,
Jani.

>
> Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/989
> Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/1031
> Link: https://gitlab.freedesktop.org/drm/xe/kernel/-/issues/1072
> Cc: Animesh Manna <animesh.manna@intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dsb.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dsb.c b/drivers/gpu/drm/i915/display/intel_dsb.c
> index 482c28b5c2de5..bc11c447afe03 100644
> --- a/drivers/gpu/drm/i915/display/intel_dsb.c
> +++ b/drivers/gpu/drm/i915/display/intel_dsb.c
> @@ -321,6 +321,7 @@ void intel_dsb_finish(struct intel_dsb *dsb)
>  	intel_dsb_buffer_flush_map(&dsb->dsb_buf);
>  }
>  
> +#ifdef I915
>  static int intel_dsb_dewake_scanline(const struct intel_crtc_state *crtc_state)
>  {
>  	struct drm_i915_private *i915 = to_i915(crtc_state->uapi.crtc->dev);
> @@ -339,6 +340,7 @@ static int intel_dsb_dewake_scanline(const struct intel_crtc_state *crtc_state)
>  
>  	return max(0, vblank_start - intel_usecs_to_scanlines(adjusted_mode, latency));
>  }
> +#endif
>  
>  static void _intel_dsb_commit(struct intel_dsb *dsb, u32 ctrl,
>  			      int dewake_scanline)
> @@ -444,6 +446,8 @@ void intel_dsb_wait(struct intel_dsb *dsb)
>  struct intel_dsb *intel_dsb_prepare(const struct intel_crtc_state *crtc_state,
>  				    unsigned int max_cmds)
>  {
> +	/* TODO: DSB is broken in Xe KMD, so disabling it until fixed */
> +#ifdef I915
>  	struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
>  	struct drm_i915_private *i915 = to_i915(crtc->base.dev);
>  	intel_wakeref_t wakeref;
> @@ -484,6 +488,7 @@ struct intel_dsb *intel_dsb_prepare(const struct intel_crtc_state *crtc_state,
>  		      "[CRTC:%d:%s] DSB %d queue setup failed, will fallback to MMIO for display HW programming\n",
>  		      crtc->base.base.id, crtc->base.name, DSB1);
>  
> +#endif
>  	return NULL;
>  }

-- 
Jani Nikula, Intel