Re: [PATCH] drm/i915: Set primary plane enable at dpcntrl.

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Thu, Jan 23, 2014 at 05:19:19PM -0200, Rodrigo Vivi wrote:
> This patch allows system to safely recover after kms_psr_sink_crc check
> or any other similar case that might fail when PSR is enabled.
> 
> Ville made and sent me this patch after noticing that primary plane enabled
> bit was set during test case and unset after failure. What was causing a hard
> and non-recoverable blank screen.
> 
> After the failure when alternating from fbcon to x section it was possible to
> see and move mouse cursor, but nothing else. Everything else was fully black.
> A for dpms off/on also haleped to get screen back. But this patch seeting
> primary plane enabled bit propertly seemed more clean.
> 
> v2: Fix identation issue.
> 
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
> ---
>  drivers/gpu/drm/i915/intel_display.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index dde98020..ed5ffce 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -2095,6 +2095,9 @@ static int i9xx_update_plane(struct drm_crtc *crtc, struct drm_framebuffer *fb,
>  	if (IS_G4X(dev))
>  		dspcntr |= DISPPLANE_TRICKLE_FEED_DISABLE;
>  
> +	if (intel_crtc->primary_enabled)
> +		dspcntr |= DISPLAY_PLANE_ENABLE;
> +
>  	I915_WRITE(reg, dspcntr);
>  
>  	linear_offset = y * fb->pitches[0] + x * (fb->bits_per_pixel / 8);
> @@ -2192,6 +2195,9 @@ static int ironlake_update_plane(struct drm_crtc *crtc,
>  	else
>  		dspcntr |= DISPPLANE_TRICKLE_FEED_DISABLE;
>  
> +	if (intel_crtc->primary_enabled)
> +		dspcntr |= DISPLAY_PLANE_ENABLE;
> +
>  	I915_WRITE(reg, dspcntr);
>  
>  	linear_offset = y * fb->pitches[0] + x * (fb->bits_per_pixel / 8);
> @@ -8586,6 +8592,11 @@ static int intel_gen7_queue_flip(struct drm_device *dev,
>  	intel_ring_emit(ring, i915_gem_obj_ggtt_offset(obj) + intel_crtc->dspaddr_offset);
>  	intel_ring_emit(ring, (MI_NOOP));
>  
> +	if (IS_VALLEYVIEW(dev) && intel_crtc->primary_enabled)
> +		I915_WRITE(DSPCNTR(intel_crtc->plane),
> +			   I915_READ(DSPCNTR(intel_crtc->plane))
> +			   | DISPLAY_PLANE_ENABLE);

We should add some kind of big comment that this ugly hack is here for
PSR. I assume we're going to remove it eventually once someone figures
out why the port/pipe/PLL aren't shutting down during PSR. To wake the
hardware back from that state takes a lot more than just flipping a
plane enable bit.

> +
>  	intel_mark_page_flip_active(intel_crtc);
>  	__intel_ring_advance(ring);
>  	return 0;
> -- 
> 1.8.1.2

-- 
Ville Syrjälä
Intel OTC