[Intel-gfx] [PATCH v3 10/11] drm/i915: Enable FIFO underrun reporting after initial fastset, v3.

[Daniel Vetter]

On Fri, Nov 10, 2017 at 12:35:02PM +0100, Maarten Lankhorst wrote:
> The firmware may have set up the pipe correctly, but the FIFO
> underrun and CRC interrupts are likely not enabled.
> 
> This resulted in debugfs_test.read_all_entries failing on haswell,
> because of a timeout when reading the crc debugfs entry.
> 
> Solve this by enabling FIFO underrun reporting after the initial
> fastset, which lets interrupts be generated as expected.
> 
> Changes since v1:
> - Always enable CPU FIFO underrun reporting for >GEN2,
>   and handle GEN2 correctly.
> Changes since v2:
> - Remove unneeded HAS_DDI, simplify GEN2 case.
> 
> Testcase: debugfs_test.read_all_entries
> Signed-off-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.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 1b75af773ef7..f0dc33fb3390 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -12906,6 +12906,7 @@ static void intel_begin_crtc_commit(struct drm_crtc *crtc,
>  static void intel_finish_crtc_commit(struct drm_crtc *crtc,
>  				     struct drm_crtc_state *old_crtc_state)
>  {
> +	struct drm_i915_private *dev_priv = to_i915(crtc->dev);
>  	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
>  	struct intel_atomic_state *old_intel_state =
>  		to_intel_atomic_state(old_crtc_state->state);
> @@ -12913,6 +12914,16 @@ static void intel_finish_crtc_commit(struct drm_crtc *crtc,
>  		intel_atomic_get_new_crtc_state(old_intel_state, intel_crtc);
>  
>  	intel_pipe_update_end(new_crtc_state);
> +
> +	if (new_crtc_state->update_pipe &&
> +	    !needs_modeset(&new_crtc_state->base) &&
> +	    old_crtc_state->mode.private_flags & I915_MODE_FLAG_INHERITED) {

Enabling fifo underruns multiple times is totally fine, we need to cope
with that (since you can a bunch of underruns, or might re-enable, or
whatever). This means you can simplify this to (old_state & INHERITED).

With that bikeshed applied:

Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>

> +		if (!IS_GEN2(dev_priv))
> +			intel_set_cpu_fifo_underrun_reporting(dev_priv, intel_crtc->pipe, true);
> +
> +		if (new_crtc_state->has_pch_encoder)
> +			intel_set_pch_fifo_underrun_reporting(dev_priv, intel_crtc->pipe, true);
> +	}
>  }
>  
>  /**
> -- 
> 2.15.0
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch