[Intel-gfx] [PATCH] drm/i915: Fix AUX power domain toggling across TypeC mode resets

[Ville Syrjälä]

On Fri, May 15, 2020 at 08:24:45PM +0300, Imre Deak wrote:
> On Fri, May 15, 2020 at 07:21:06PM +0300, Ville Syrjälä wrote:
> > On Thu, May 14, 2020 at 11:45:53PM +0300, Imre Deak wrote:
> > > Make sure to select the port's AUX power domain while holding the TC
> > > port lock. The domain depends on the port's current TC mode, which may
> > > get changed under us if we're not holding the lock.
> > 
> > Can we toss in a lockdep assert?
> 
> Yes, can do that. However, now I realize, there is one more place to fix
> in intel_dp_force(), where I think we could just drop the aux get/put.
> 
> So are you ok to do that as a follow-up?

Sure.

> 
> > Did this by any chance help with the MST issues you were seeing?
> 
> No, at least it didn't resolve it. Still some missing responses to MST
> down messages. More precisely the sink does send interrupts as a
> response, but the interrupt handler won't see the DP_DOWN_REP_MSG_RDY
> being set in ESI.

:(

> 
> > > This was left out from
> > > commit 8c10e2262663 ("drm/i915: Keep the TypeC port mode fixed for detect/AUX transfers")
> > > 
> > > Cc: <stable at vger.kernel.org> # v5.4+
> > > Signed-off-by: Imre Deak <imre.deak at intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/display/intel_dp.c | 5 +++--
> > >  1 file changed, 3 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
> > > index 408c3c1c5e81..40d42dcff0b7 100644
> > > --- a/drivers/gpu/drm/i915/display/intel_dp.c
> > > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> > > @@ -1359,8 +1359,7 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp,
> > >  	bool is_tc_port = intel_phy_is_tc(i915, phy);
> > >  	i915_reg_t ch_ctl, ch_data[5];
> > >  	u32 aux_clock_divider;
> > > -	enum intel_display_power_domain aux_domain =
> > > -		intel_aux_power_domain(intel_dig_port);
> > > +	enum intel_display_power_domain aux_domain;
> > >  	intel_wakeref_t aux_wakeref;
> > >  	intel_wakeref_t pps_wakeref;
> > >  	int i, ret, recv_bytes;
> > > @@ -1375,6 +1374,8 @@ intel_dp_aux_xfer(struct intel_dp *intel_dp,
> > >  	if (is_tc_port)
> > >  		intel_tc_port_lock(intel_dig_port);
> > >  
> > > +	aux_domain = intel_aux_power_domain(intel_dig_port);
> > > +
> > >  	aux_wakeref = intel_display_power_get(i915, aux_domain);
> > >  	pps_wakeref = pps_lock(intel_dp);
> > >  
> > > -- 
> > > 2.23.1
> > > 
> > > _______________________________________________
> > > Intel-gfx mailing list
> > > Intel-gfx at lists.freedesktop.org
> > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > 
> > -- 
> > Ville Syrjälä
> > Intel

-- 
Ville Syrjälä
Intel