On Mon, 2017-12-11 at 23:32 +0000, Runyan, Arthur J wrote: > You're right. DC5 could disrupt GMBUS. We forgot to add a note on GMBUS when it got moved under DMC domain in GLK and BXT/APL. I'll take care of that. > In light of this confirmation, patches 1 and 2 are Reviewed-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@xxxxxxxxx> > -----Original Message----- > From: Ville Syrjälä [mailto:ville.syrjala@xxxxxxxxxxxxxxx] > Sent: Monday, 11 December, 2017 11:03 AM > To: Pandiyan, Dhinakaran <dhinakaran.pandiyan@xxxxxxxxx> > Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx; stable@xxxxxxxxxxxxxxx; Runyan, Arthur J <arthur.j.runyan@xxxxxxxxx> > Subject: Re: [PATCH 1/4] drm/i915: Disable DC states around GMBUS on GLK > > On Mon, Dec 11, 2017 at 06:41:05PM +0000, Pandiyan, Dhinakaran wrote: > > On Fri, 2017-12-08 at 23:37 +0200, Ville Syrjala wrote: > > > From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > > > > > Prevent the DMC from destroying GMBUS transfers on GLK. GMBUS > > > lives in PG1 so DC off is all we need. > > > > > Just so that I understand this correctly. DMC is expected to take care > > of managing power for GMBUS transfers without the driver explicitly > > turning on/off the power well 1 but it isn't. Do you know if this is a > > DMC regression? > > No idea. The docs don't seem to even mention DMC and GMBUS in the same > sentence. But since DP AUX needs DC off I don't see why GMBUS would > be all that different. > > And with bit banging I would be somewhat surprised if DMC could > maintain the state of the pins while in DC5. Although I suppose it > might be possible that the hw automagically prevents DC5 when we're > driving any of the pins. > > Art? > > > > > > Cc: stable@xxxxxxxxxxxxxxx > > > Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > > > --- > > > drivers/gpu/drm/i915/intel_runtime_pm.c | 1 + > > > 1 file changed, 1 insertion(+) > > > > > > diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c > > > index 96ab74f3d101..522e0a63090f 100644 > > > --- a/drivers/gpu/drm/i915/intel_runtime_pm.c > > > +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c > > > @@ -1792,6 +1792,7 @@ void intel_display_power_put(struct drm_i915_private *dev_priv, > > > BIT_ULL(POWER_DOMAIN_GT_IRQ) | \ > > > BIT_ULL(POWER_DOMAIN_MODESET) | \ > > > BIT_ULL(POWER_DOMAIN_AUX_A) | \ > > > + BIT_ULL(POWER_DOMAIN_GMBUS) | \ > > > BIT_ULL(POWER_DOMAIN_INIT)) > > > > > > #define CNL_DISPLAY_POWERWELL_2_POWER_DOMAINS ( \ > _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
