FAILED: patch "[PATCH] drm/i915: Remove non-existent pipes from bigjoiner pipe mask" failed to apply to 6.0-stable tree

The patch below does not apply to the 6.0-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Possible dependencies:

ddb97ea7cdb6 ("drm/i915: Remove non-existent pipes from bigjoiner pipe mask")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From ddb97ea7cdb6462d7a719c649f58858b083f7eed Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= <[email protected]>
Date: Fri, 18 Nov 2022 20:52:01 +0200
Subject: [PATCH] drm/i915: Remove non-existent pipes from bigjoiner pipe mask
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bigjoiner_pipes() doesn't consider that:
- RKL only has three pipes
- some pipes may be fused off

This means that intel_atomic_check_bigjoiner() won't reject all configurations that would need a non-existent pipe. Instead we just keep on rolling witout actually having reserved the slave pipe we need.

It's possible that we don't outright explode anywhere due to this since eg. for_each_intel_crtc_in_pipe_mask() will only walk the crtcs we've registered even though the passed in pipe_mask asks for more of them. But clearly the thing won't do what is expected of it when the required pipes are not present.

Fix the problem by consulting the device info pipe_mask already in bigjoiner_pipes().

index b3e23708d194..6c2686ecb62a 100644
@@ -3733,12 +3733,16 @@ static bool ilk_get_pipe_config(struct intel_crtc *crtc,
 
 static u8 bigjoiner_pipes(struct drm_i915_private *i915)
 {
+	u8 pipes;
+
 	if (DISPLAY_VER(i915) >= 12)
-		return BIT(PIPE_A) | BIT(PIPE_B) | BIT(PIPE_C) | BIT(PIPE_D);
+		pipes = BIT(PIPE_A) | BIT(PIPE_B) | BIT(PIPE_C) | BIT(PIPE_D);
 	else if (DISPLAY_VER(i915) >= 11)
-		return BIT(PIPE_B) | BIT(PIPE_C);
+		pipes = BIT(PIPE_B) | BIT(PIPE_C);
 	else
-		return 0;
+		pipes = 0;
+
+	return pipes & RUNTIME_INFO(i915)->pipe_mask;
 }
 
 static bool transcoder_ddi_func_is_enabled(struct drm_i915_private *dev_priv,