From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Fri, 8 Jun 2018 18:32:21 +0100
Subject: drm/i915/gtt: Fix unwind length passed to gen6_ppgtt_clear_range
Git-commit: b4e2727df2713a5aea9de6364f7a943147ceef92
Patch-mainline: v4.19-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

When we want to unwind an error when allocating the PD for gen6, we call
gen6_ppgtt_clear_range() telling to clear upto the PD we've previously
allocated. However, we passed it an incorrect length, passing it the
endpoint instead. Fortunately, as the start was always 0, this has no
impact today, but tomorrow we want to start using non-zero origins.

Reported-by: Matthew Auld <matthew.william.auld@gmail.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Matthew Auld <matthew.william.auld@gmail.com>
Reviewed-by: Matthew Auld <matthew.william.auld@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180608173221.10455-1-chris@chris-wilson.co.uk

Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/i915/i915_gem_gtt.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -1931,7 +1931,7 @@ static int gen6_alloc_va_range(struct i9
 	return 0;
 
 unwind_out:
-	gen6_ppgtt_clear_range(vm, from, start);
+	gen6_ppgtt_clear_range(vm, from, start - from);
 	return -ENOMEM;
 }