[Intel-gfx] [PATCH 2/3] drm/i915: Do drm_mode_config_reset() after HPD init

[Imre Deak]

On Tue, Oct 06, 2020 at 09:58:08PM +0300, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> LSPCON requires HPD detection logic to be enabled when we call
> its .reset() hook during resume, to check the live state of the
> pin. To that end let's reorder the resume sequence such that
> we do HPD init before the encoder reset.
> 
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.c | 7 +++----
>  1 file changed, 3 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> index b2a050d916e3..66ddd4161885 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1213,21 +1213,20 @@ static int i915_drm_resume(struct drm_device *dev)
>  	 * GPU will hang. i915_gem_init_hw() will initiate batches to
>  	 * update/restore the context.
>  	 *
> -	 * drm_mode_config_reset() needs AUX interrupts.
> -	 *
>  	 * Modeset enabling in intel_modeset_init_hw() also needs working
>  	 * interrupts.
>  	 */
>  	intel_runtime_pm_enable_interrupts(dev_priv);
>  
> -	drm_mode_config_reset(dev);
> -
>  	i915_gem_resume(dev_priv);
>  
>  	intel_modeset_init_hw(dev_priv);
>  	intel_init_clock_gating(dev_priv);
>  	intel_hpd_init(dev_priv);
>  
> +	/* May need AUX interrupts and HPD detection enabled */
> +	drm_mode_config_reset(dev);

lspcon_resume() could be called both by the above and during connector
detection. Delaying hotplug detection until after intel_display_resume()
would be the ideal solution, but until that we could avoid this race by
taking connection_mutex.

> +
>  	/* MST sideband requires HPD interrupts enabled */
>  	intel_dp_mst_resume(dev_priv);
>  	intel_display_resume(dev);
> -- 
> 2.26.2
> 
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