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

[Souza, Jose]

On Wed, 2024-01-03 at 17:37 +0200, Jani Nikula wrote:
> On Wed, 03 Jan 2024, José Roberto de Souza <jose.souza at 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.

Like this is enough?

+/* TODO: DSB is broken in Xe KMD, so disabling it until fixed */
+#ifdef I915
 #define HAS_DSB(i915)                  (DISPLAY_INFO(i915)->has_dsb)
+#else
+#define HAS_DSB(i915)                  (false)
+#endif


> 
> 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 at intel.com>
> > Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> > Signed-off-by: José Roberto de Souza <jose.souza at 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;
> >  }
>