[Intel-gfx] [PATCH v2] drm/i915/psr: Preserve SRD_CTL bit 29 on PSR init

[Rodrigo Vivi]

Reviewed-by: Rodrigo Vivi <rodrigo.vivi at intel.com>

On Tue, Aug 8, 2017 at 2:51 PM, Jim Bride <jim.bride at linux.intel.com> wrote:
> Bit 29 of SRD_CTL needs to have its value preserved according to the
> B-Spec, so right before we write out the register we go ahead and read
> the register and preserve the value of that bit before we write out
> the configured register value.
>
> v2: Spaces => tabs, minor name change, and commit message wording (Rodrigo)
>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Jani Nikula <jani.nikula at intel.com>
> Signed-off-by: Jim Bride <jim.bride at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_reg.h  | 1 +
>  drivers/gpu/drm/i915/intel_psr.c | 1 +
>  2 files changed, 2 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index b2546ad..56df86e 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -3872,6 +3872,7 @@ enum {
>  #define EDP_PSR_CTL                            _MMIO(dev_priv->psr_mmio_base + 0)
>  #define   EDP_PSR_ENABLE                       (1<<31)
>  #define   BDW_PSR_SINGLE_FRAME                 (1<<30)
> +#define   EDP_PSR_RESTORE_PSR_ACTIVE_CTX_MASK  (1<<29) /* SW can't modify */
>  #define   EDP_PSR_LINK_STANDBY                 (1<<27)
>  #define   EDP_PSR_MIN_LINK_ENTRY_TIME_MASK     (3<<25)
>  #define   EDP_PSR_MIN_LINK_ENTRY_TIME_8_LINES  (0<<25)
> diff --git a/drivers/gpu/drm/i915/intel_psr.c b/drivers/gpu/drm/i915/intel_psr.c
> index 559f1ab..1b31ab0 100644
> --- a/drivers/gpu/drm/i915/intel_psr.c
> +++ b/drivers/gpu/drm/i915/intel_psr.c
> @@ -315,6 +315,7 @@ static void intel_enable_source_psr1(struct intel_dp *intel_dp)
>         else
>                 val |= EDP_PSR_TP1_TP2_SEL;
>
> +       val |= I915_READ(EDP_PSR_CTL) & EDP_PSR_RESTORE_PSR_ACTIVE_CTX_MASK;
>         I915_WRITE(EDP_PSR_CTL, val);
>  }
>
> --
> 2.7.4
>
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-- 
Rodrigo Vivi
Blog: http://blog.vivi.eng.br