Re: [Intel-gfx] [V2 3/4] drm/i915/dsi/xelpd: Disable DC states in Video mode

[Imre Deak <imre.deak@intel.com>]

On Thu, Oct 28, 2021 at 04:53:22PM +0300, Kulkarni, Vandita wrote:
> > -----Original Message-----
> > From: Deak, Imre <imre.deak@intel.com>
> > Sent: Saturday, October 23, 2021 1:53 AM
> > To: Kulkarni, Vandita <vandita.kulkarni@intel.com>
> > Cc: intel-gfx@lists.freedesktop.org; Nikula, Jani <jani.nikula@intel.com>;
> > Roper, Matthew D <matthew.d.roper@intel.com>;
> > ville.syrjala@linux.intel.com
> > Subject: Re: [V2 3/4] drm/i915/dsi/xelpd: Disable DC states in Video mode
> > 
> > On Tue, Oct 19, 2021 at 08:44:34PM +0530, Vandita Kulkarni wrote:
> > > MIPI DSI transcoder cannot be in video mode to support any of the
> > > display C states.
> > >
> > > Bspec: 49195 (For DC*co DSI transcoders cannot be in video mode)
> > > Bspec: 49193 (Hardware does not support DC5 or DC6 with MIPI DSI
> > > enabled)
> > > Bspec: 49188 (desc of DSI_DCSTATE_CTL talks about cmd mode PM control
> > 
> > So none of the DC states (except DC6v which the driver doesn't support) are
> > supported in DSI video mode and DC3co is supported in command mode.
> > The selection between video vs. command mode happens using a VBT flag
> > and I can't see anything that would prevent using command mode on XELPD.
> > If the support for it is missing, should it be disabled explicitly or at least a
> > notice printed that DC states are not yet supported?
> 
> Since we haven't enabled and tried dsi cmd mode on xelpd and in DC3co
> DMC Would monitor the idleness of the transcoder, until that is
> enabled, we can disable Cmd mode for now.  Will send out a patch to
> disable cmd mode on xelpd, as it would by default depend on Vbt like
> you have mentioned above.

Ok. On this patch:
Reviewed-by: Imre Deak <imre.deak@intel.com>

> 
> Thanks,
> Vandita
>  
> > 
> > > v2: Align to the power domain ordering (Jani)
> > >     Add bspec references (Imre)
> > >
> > > Signed-off-by: Vandita Kulkarni <vandita.kulkarni@intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/display/intel_display_power.c | 1 +
> > >  1 file changed, 1 insertion(+)
> > >
> > > diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c
> > > b/drivers/gpu/drm/i915/display/intel_display_power.c
> > > index d88da0d0f05a..b989ddd3d023 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_display_power.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_display_power.c
> > > @@ -3106,6 +3106,7 @@ intel_display_power_put_mask_in_set(struct
> > drm_i915_private *i915,
> > >  	BIT_ULL(POWER_DOMAIN_MODESET) |			\
> > >  	BIT_ULL(POWER_DOMAIN_AUX_A) |			\
> > >  	BIT_ULL(POWER_DOMAIN_AUX_B) |			\
> > > +	BIT_ULL(POWER_DOMAIN_PORT_DSI) |		\
> > >  	BIT_ULL(POWER_DOMAIN_INIT))
> > >
> > >  #define XELPD_AUX_IO_D_XELPD_POWER_DOMAINS
> > 	BIT_ULL(POWER_DOMAIN_AUX_D_XELPD)
> > > --
> > > 2.32.0
> > >