[Intel-gfx] [PATCH] drm/i915/dsc: Remove redundant checks in DSC disable

[Manna, Animesh]

> -----Original Message-----
> From: Kulkarni, Vandita <vandita.kulkarni at intel.com>
> Sent: Thursday, June 3, 2021 4:55 PM
> To: Nikula, Jani <jani.nikula at intel.com>; Saarinen, Jani
> <jani.saarinen at intel.com>; intel-gfx at lists.freedesktop.org
> Cc: Manna, Animesh <animesh.manna at intel.com>; Navare, Manasi D
> <manasi.d.navare at intel.com>
> Subject: RE: [Intel-gfx] [PATCH] drm/i915/dsc: Remove redundant checks in DSC
> disable
> 
> > -----Original Message-----
> > From: Nikula, Jani <jani.nikula at intel.com>
> > Sent: Thursday, June 3, 2021 3:11 PM
> > To: Kulkarni, Vandita <vandita.kulkarni at intel.com>; Saarinen, Jani
> > <jani.saarinen at intel.com>; intel-gfx at lists.freedesktop.org
> > Cc: Manna, Animesh <animesh.manna at intel.com>; Navare, Manasi D
> > <manasi.d.navare at intel.com>
> > Subject: RE: [Intel-gfx] [PATCH] drm/i915/dsc: Remove redundant checks
> > in DSC disable
> >
> > On Thu, 03 Jun 2021, "Kulkarni, Vandita" <vandita.kulkarni at intel.com>
> > wrote:
> > >> -----Original Message-----
> > >> From: Saarinen, Jani <jani.saarinen at intel.com>
> > >> Sent: Thursday, June 3, 2021 1:07 PM
> > >> To: Kulkarni, Vandita <vandita.kulkarni at intel.com>; intel-
> > >> gfx at lists.freedesktop.org
> > >> Cc: Nikula, Jani <jani.nikula at intel.com>
> > >> Subject: RE: [Intel-gfx] [PATCH] drm/i915/dsc: Remove redundant
> > >> checks in DSC disable
> > >>
> > >> Hi,
> > >> > -----Original Message-----
> > >> > From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On
> > >> > Behalf Of Vandita Kulkarni
> > >> > Sent: torstai 3. kesäkuuta 2021 9.54
> > >> > To: intel-gfx at lists.freedesktop.org
> > >> > Cc: Nikula, Jani <jani.nikula at intel.com>
> > >> > Subject: [Intel-gfx] [PATCH] drm/i915/dsc: Remove redundant
> > >> > checks in DSC disable
> > >> >
> > >> > There can be a chance that pre os has enabled DSC and driver's
> > >> > compute config would not need dsc to be enabled, in such case if
> > >> > we check on compute config's compression state to disable, we
> > >> > might end up in state
> > >> mismatch.
> > >>
> > >> I assume this fixes real gitlab issue too?
> > > Okay, will add the tag
> > > Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/3537
> >
> > See https://lore.kernel.org/r/87fsxzp9qx.fsf@intel.com
> >
> > The problem is with ->bigjoiner, not the entire statement.
> Thanks for pointing this out, true that bigjoiner not being enabled will stop dsc
> disabling.
> The bigjoiner check was making the entire condition check unnecessary.
> 
> Will update and refloat.

Hi Jani/Vandita,

For uncompressed bigjoiner case if we want to use the same function to clear the dsc_ctrl1 register we may need to remove both the condition check.
As for uncompressed bigjoiner case, compression_enable Will be 0 and will block in clearing the dss_ctl1_reg.

Regards,
Animesh
> 
> Thanks,
> Vandita
> >
> >
> > BR,
> > Jani.
> >
> > >
> > > Thanks,
> > > Vandita
> > >>
> > >> >
> > >> > Signed-off-by: Vandita Kulkarni <vandita.kulkarni at intel.com>
> > >> > ---
> > >> >  drivers/gpu/drm/i915/display/intel_vdsc.c | 4 ----
> > >> >  1 file changed, 4 deletions(-)
> > >> >
> > >> > diff --git a/drivers/gpu/drm/i915/display/intel_vdsc.c
> > >> > b/drivers/gpu/drm/i915/display/intel_vdsc.c
> > >> > index 19cd9531c115..b05a96011d93 100644
> > >> > --- a/drivers/gpu/drm/i915/display/intel_vdsc.c
> > >> > +++ b/drivers/gpu/drm/i915/display/intel_vdsc.c
> > >> > @@ -1161,10 +1161,6 @@ void intel_dsc_disable(const struct
> > >> > intel_crtc_state
> > >> > *old_crtc_state)
> > >> >  	struct intel_crtc *crtc = to_intel_crtc(old_crtc_state->uapi.crtc);
> > >> >  	struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
> > >> >
> > >> > -	if (!(old_crtc_state->dsc.compression_enable &&
> > >> > -	      old_crtc_state->bigjoiner))
> > >> > -		return;
> > >> > -
> > >> >  	intel_de_write(dev_priv, dss_ctl1_reg(old_crtc_state), 0);
> > >> >  	intel_de_write(dev_priv, dss_ctl2_reg(old_crtc_state), 0);  }
> > >> > --
> > >> > 2.21.0.5.gaeb582a
> > >> >
> > >> > _______________________________________________
> > >> > Intel-gfx mailing list
> > >> > Intel-gfx at lists.freedesktop.org
> > >> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> >
> > --
> > Jani Nikula, Intel Open Source Graphics Center