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

[Jesse Barnes <jbarnes@virtuousgeek.org>]

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?

Thanks,
-- 
Jesse Barnes, Intel Open Source Technology Center