Re: [PATCH] drm/i915/gen9+: Fix initial readout for Y tiled framebuffers

["Life is hard, and then you die" <ronald@innovation.ch>]

On Tue, Oct 16, 2018 at 07:00:11PM +0300, Imre Deak wrote:
> If BIOS configured a Y tiled FB we failed to set up the backing object
> tiling accordingly, leading to a lack of GT fence installed and a
> garbled console.
> 
> The problem was bisected to
> commit 011f22eb545a ("drm/i915: Do NOT skip the first 4k of stolen memory for pre-allocated buffers v2")
> but it just revealed a pre-existing issue.
> 
> Kudos to Ville who suspected a missing fence looking at the corruption
> on the screen.
> 
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
> Cc: Hans de Goede <hdegoede@redhat.com>
> Cc: ronald@innovation.ch
> Cc: <stable@vger.kernel.org>
> Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> Reported-by: ronald@innovation.ch
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108264
> Fixes: bc8d7dffacb1 ("drm/i915/skl: Provide a Skylake version of get_plane_config()")
> Signed-off-by: Imre Deak <imre.deak@intel.com>

I can confirm it fixes the issue for MBP13,3 (Skylake) on kernels
4.18.14, 4.19.0-rc8, and drm-tip.


  Cheers,

  Ronald


> ---
>  drivers/gpu/drm/i915/intel_display.c | 25 +++++++++++++++++++++++--
>  1 file changed, 23 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index a2e729fa8d64..3d34b98c4634 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -2674,6 +2674,17 @@ intel_alloc_initial_plane_obj(struct intel_crtc *crtc,
>  	if (size_aligned * 2 > dev_priv->stolen_usable_size)
>  		return false;
>  
> +	switch (fb->modifier) {
> +	case DRM_FORMAT_MOD_LINEAR:
> +	case I915_FORMAT_MOD_X_TILED:
> +	case I915_FORMAT_MOD_Y_TILED:
> +		break;
> +	default:
> +		DRM_DEBUG_DRIVER("Unsupported modifier for initial FB: 0x%llx\n",
> +				 fb->modifier);
> +		return false;
> +	}
> +
>  	mutex_lock(&dev->struct_mutex);
>  	obj = i915_gem_object_create_stolen_for_preallocated(dev_priv,
>  							     base_aligned,
> @@ -2683,8 +2694,17 @@ intel_alloc_initial_plane_obj(struct intel_crtc *crtc,
>  	if (!obj)
>  		return false;
>  
> -	if (plane_config->tiling == I915_TILING_X)
> -		obj->tiling_and_stride = fb->pitches[0] | I915_TILING_X;
> +	switch (plane_config->tiling) {
> +	case I915_TILING_NONE:
> +		break;
> +	case I915_TILING_X:
> +	case I915_TILING_Y:
> +		obj->tiling_and_stride = fb->pitches[0] | plane_config->tiling;
> +		break;
> +	default:
> +		MISSING_CASE(plane_config->tiling);
> +		return false;
> +	}
>  
>  	mode_cmd.pixel_format = fb->format->format;
>  	mode_cmd.width = fb->width;
> @@ -8827,6 +8847,7 @@ skylake_get_initial_plane_config(struct intel_crtc *crtc,
>  		fb->modifier = I915_FORMAT_MOD_X_TILED;
>  		break;
>  	case PLANE_CTL_TILED_Y:
> +		plane_config->tiling = I915_TILING_Y;
>  		if (val & PLANE_CTL_RENDER_DECOMPRESSION_ENABLE)
>  			fb->modifier = I915_FORMAT_MOD_Y_TILED_CCS;
>  		else
> -- 
> 2.13.2
>