[Intel-gfx] [PATCH 08/11] drm/i915/adl_p: Add stride restriction when using DPT

[Imre Deak]

From: José Roberto de Souza <jose.souza at intel.com>

Alderlake-P have a new stride restriction when using DPT and it is used
by non linear framebuffers. Stride needs to be a power of two to take
full DPT rows, but stride is a parameter set by userspace.

What we could do is use a fake stride when doing DPT allocation so
HW requirements are met and userspace don't need to be changed to
met this power of two restrictions but this change will take a while
to be implemented so for now adding this restriction in driver to
reject atomic commits that would cause visual corruptions.

BSpec: 53393
Acked-by: Matt Roper <matthew.d.roper at intel.com>
Cc: Matt Roper <matthew.d.roper at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
---
 drivers/gpu/drm/i915/display/intel_display.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
index ce685a7ba6a1d..2eba13898fbea 100644
--- a/drivers/gpu/drm/i915/display/intel_display.c
+++ b/drivers/gpu/drm/i915/display/intel_display.c
@@ -11558,6 +11558,15 @@ static int intel_framebuffer_init(struct intel_framebuffer *intel_fb,
 			}
 		}
 
+		if (IS_ALDERLAKE_P(dev_priv) &&
+		    mode_cmd->modifier[i] != DRM_FORMAT_MOD_LINEAR &&
+		    !is_power_of_2(mode_cmd->pitches[i])) {
+			drm_dbg_kms(&dev_priv->drm,
+				    "plane %d pitch (%d) must be power of two for tiled buffers\n",
+				    i, mode_cmd->pitches[i]);
+			goto err;
+		}
+
 		fb->obj[i] = &obj->base;
 	}
 
-- 
2.27.0