Re: [PATCH 2/4] drm/i915: Remove PSR HW tracking.

[Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>]

On Thu, Sep 4, 2014 at 1:06 AM, Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> wrote:

On Wed, Sep 03, 2014 at 10:49:57PM -0400, Rodrigo Vivi wrote:
> Now that we are tracking psr states on Software side we don't need HW help anymore.
> So we can clean up the code a bit and avoid unecessary sets.
>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
> ---
>  drivers/gpu/drm/i915/intel_dp.c | 12 ------------
>  1 file changed, 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index a796831..9414e67 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -1778,10 +1778,7 @@ static void intel_edp_psr_enable_sink(struct intel_dp *intel_dp)
>  {
>       struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
>       struct drm_device *dev = dig_port->base.base.dev;
> -     struct drm_i915_private *dev_priv = dev->dev_private;
>       uint32_t aux_clock_divider;
> -     int precharge = 0x3;
> -     int msg_size = 5;       /* Header(4) + Message(1) */
>       bool _only_standby_ = false;
>
>       aux_clock_divider = intel_dp->get_aux_clock_divider(intel_dp, 0);
> @@ -1796,15 +1793,6 @@ static void intel_edp_psr_enable_sink(struct intel_dp *intel_dp)
>       else
>               drm_dp_dpcd_writeb(&intel_dp->aux, DP_PSR_EN_CFG,
>                                  DP_PSR_ENABLE | DP_PSR_MAIN_LINK_ACTIVE);
> -
> -     /* Setup AUX registers */
> -     I915_WRITE(EDP_PSR_AUX_DATA1(dev), EDP_PSR_DPCD_COMMAND);
> -     I915_WRITE(EDP_PSR_AUX_DATA2(dev), EDP_PSR_DPCD_NORMAL_OPERATION);
> -     I915_WRITE(EDP_PSR_AUX_CTL(dev),
> -                DP_AUX_CH_CTL_TIME_OUT_400us |
> -                (msg_size << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT) |
> -                (precharge << DP_AUX_CH_CTL_PRECHARGE_2US_SHIFT) |
> -                (aux_clock_divider << DP_AUX_CH_CTL_BIT_CLOCK_2X_SHIFT));

As I said I blieve FBC is the one that does the hw tracking. I think the
hardware will still do the entry/exit (including automagic link
re-train) but now you've not told it how to wake up the sink. So I don't
understand how this can even work.

Per spec we have to program aux "registers for HW assist PSR Exit Support."

With the exit being made on SW side we don't need HW help anymore.

Same reason why this works with VLV.

But there is no way to claim full control. So automagically triggers still exist.

So I couldn't remove the W/As that mask events on srd_debug. :(

But withouth these aux sets we are fine and it just works.

 

>  }
>
>  static void intel_edp_psr_enable_source(struct intel_dp *intel_dp)
> --
> 1.9.3
>
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--
Ville Syrjälä
Intel OTC

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--

Rodrigo Vivi

Blog: http://blog.vivi.eng.br

 

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