[Intel-gfx] [PATCH] drm/i915/fbdev: Actually configure untiled displays

[Maarten Lankhorst]

Op 15-02-2019 om 13:30 schreef Chris Wilson:
> If we skipped all the connectors that were not part of a tile, we would
> leave conn_seq=0 and conn_configured=0, convincing ourselves that we
> had stagnated in our configuration attempts. Avoid this situation by
> starting conn_seq=ALL_CONNECTORS, and repeating until we find no more
> connectors to configure.
>
> Fixes: 754a76591b12 ("drm/i915/fbdev: Stop repeating tile configuration on stagnation")
> Reported-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> ---
>  drivers/gpu/drm/i915/intel_fbdev.c | 12 +++++++-----
>  1 file changed, 7 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_fbdev.c b/drivers/gpu/drm/i915/intel_fbdev.c
> index 376ffe842e26..e8f694b57b8a 100644
> --- a/drivers/gpu/drm/i915/intel_fbdev.c
> +++ b/drivers/gpu/drm/i915/intel_fbdev.c
> @@ -338,8 +338,8 @@ static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
>  				    bool *enabled, int width, int height)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(fb_helper->dev);
> -	unsigned long conn_configured, conn_seq, mask;
>  	unsigned int count = min(fb_helper->connector_count, BITS_PER_LONG);
> +	unsigned long conn_configured, conn_seq;
>  	int i, j;
>  	bool *save_enabled;
>  	bool fallback = true, ret = true;
> @@ -357,10 +357,9 @@ static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
>  		drm_modeset_backoff(&ctx);
>  
>  	memcpy(save_enabled, enabled, count);
> -	mask = GENMASK(count - 1, 0);
> +	conn_seq = GENMASK(count - 1, 0);
>  	conn_configured = 0;
>  retry:
> -	conn_seq = conn_configured;
>  	for (i = 0; i < count; i++) {
>  		struct drm_fb_helper_connector *fb_conn;
>  		struct drm_connector *connector;
> @@ -373,7 +372,8 @@ static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
>  		if (conn_configured & BIT(i))
>  			continue;
>  
> -		if (conn_seq == 0 && !connector->has_tile)
> +		/* First pass, only consider tiled connectors */
> +		if (conn_seq == GENMASK(count - 1, 0) && !connector->has_tile)
>  			continue;
>  
>  		if (connector->status == connector_status_connected)
> @@ -477,8 +477,10 @@ static bool intel_fb_initial_config(struct drm_fb_helper *fb_helper,
>  		conn_configured |= BIT(i);
>  	}
>  
> -	if ((conn_configured & mask) != mask && conn_configured != conn_seq)
> +	if (conn_configured != conn_seq) { /* repeat until no more are found */
> +		conn_seq = conn_configured;
>  		goto retry;
> +	}
>  
>  	/*
>  	 * If the BIOS didn't enable everything it could, fall back to have the

Seems safer than the previous version.

We should really unloop this in a helper, but this is ok for now if BAT passes.

Reviewed-by: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>