[Intel-gfx] [PATCH v2 3/6] drm/i915: Enable async flips in i915

[Paulo Zanoni]

Em seg, 2020-04-20 às 15:17 +0530, Karthik B S escreveu:
> Enable asynchronous flips in i915 for gen9+ platforms.
> 
> v2: -Async flip enablement should be a stand alone patch (Paulo)

... and at the very end of the series.

If someone is bisecting the Kernel for some problem unrelated to async
flips, and they end up exactly at this commit, and their user space
happens to try to do async flips, will their system be broken? A quick
check at patches 4, 5 and 6 suggests they are necessary for the feature
to work, so here we're enabling a feature that we know won't work
because its support is not fully merged yet.

A patch series is not allowed to break the Kernel in the middle and
then fix it later.

> 
> Signed-off-by: Karthik B S <karthik.b.s at intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index cf8f5779dee4..8601b159f425 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -17574,6 +17574,9 @@ static void intel_mode_config_init(struct drm_i915_private *i915)
>  
>  	mode_config->funcs = &intel_mode_funcs;
>  
> +	if (INTEL_GEN(i915) >= 9)
> +		mode_config->async_page_flip = true;
> +
>  	/*
>  	 * Maximum framebuffer dimensions, chosen to match
>  	 * the maximum render engine surface size on gen4+.