Re: [PATCH 2/2] drm/i915: vlv/chv: fix DSI sideband register accessing

[Jesse Barnes <jbarnes@virtuousgeek.org>]

On Mon, 19 May 2014 18:10:18 +0300
Imre Deak <imre.deak@intel.com> wrote:

> On Mon, 2014-05-19 at 08:01 -0700, Jesse Barnes wrote:
> > On Mon, 19 May 2014 11:41:18 +0300
> > Imre Deak <imre.deak@intel.com> wrote:
> > 
> > > So far we used the wrong opcodes to access the DSI registers, so the
> > > register writes during DSI programming didn't actually succeed and left
> > > the registers unchanged. This wasn't a problem for the initial modeset,
> > > where the BIOS-programmed values happened to work, but after resuming
> > > from s0ix these registers are reset and failing to program them results
> > > in a blank screen.
> > > 
> > > Signed-off-by: Imre Deak <imre.deak@intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/intel_sideband.c | 4 ++--
> > >  1 file changed, 2 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/intel_sideband.c b/drivers/gpu/drm/i915/intel_sideband.c
> > > index f3909d5..01d841e 100644
> > > --- a/drivers/gpu/drm/i915/intel_sideband.c
> > > +++ b/drivers/gpu/drm/i915/intel_sideband.c
> > > @@ -270,13 +270,13 @@ void intel_sbi_write(struct drm_i915_private *dev_priv, u16 reg, u32 value,
> > >  u32 vlv_flisdsi_read(struct drm_i915_private *dev_priv, u32 reg)
> > >  {
> > >  	u32 val = 0;
> > > -	vlv_sideband_rw(dev_priv, DPIO_DEVFN, IOSF_PORT_FLISDSI, SB_MRD_NP,
> > > +	vlv_sideband_rw(dev_priv, DPIO_DEVFN, IOSF_PORT_FLISDSI, SB_CRRDDA_NP,
> > >  			reg, &val);
> > >  	return val;
> > >  }
> > >  
> > >  void vlv_flisdsi_write(struct drm_i915_private *dev_priv, u32 reg, u32 val)
> > >  {
> > > -	vlv_sideband_rw(dev_priv, DPIO_DEVFN, IOSF_PORT_FLISDSI, SB_MWR_NP,
> > > +	vlv_sideband_rw(dev_priv, DPIO_DEVFN, IOSF_PORT_FLISDSI, SB_CRWRDA_NP,
> > >  			reg, &val);
> > >  }
> > 
> > Nice find... is this documented somewhere so we can put a reference
> > in?  Or is it in the Punit HAS somewhere already and we just missed it?
> 
> I found it in the VLV2_SidebandMsg_HAS, there is already a comment in
> this file with a reference to it.

Cool, this one has my
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
then too.

-- 
Jesse Barnes, Intel Open Source Technology Center