[PATCH v2 1/6] drm/i915/gem: fix bitwise and logical AND mixup

Jani Nikula jani.nikula at intel.com
Wed Sep 18 17:35:43 UTC 2024


CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND is an int, defaulting to 250. When
the wakeref is non-zero, it's either -1 or a dynamically allocated
pointer, depending on CONFIG_DRM_I915_DEBUG_RUNTIME_PM. It's likely that
the code works by coincidence with the bitwise AND, but with
CONFIG_DRM_I915_DEBUG_RUNTIME_PM=y, there's the off chance that the
condition evaluates to false, and intel_wakeref_auto() doesn't get
called. Switch to the intended logical AND.

v2: Use != to avoid clang -Wconstant-logical-operand (Nathan)

Fixes: ad74457a6b5a ("drm/i915/dgfx: Release mmap on rpm suspend")
Cc: Matthew Auld <matthew.auld at intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
Cc: Anshuman Gupta <anshuman.gupta at intel.com>
Cc: Andi Shyti <andi.shyti at linux.intel.com>
Cc: Nathan Chancellor <nathan at kernel.org>
Cc: <stable at vger.kernel.org> # v6.1+
Reviewed-by: Matthew Auld <matthew.auld at intel.com> # v1
Reviewed-by: Andi Shyti <andi.shyti at linux.intel.com> # v1
Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_ttm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
index 5c72462d1f57..b22e2019768f 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_ttm.c
@@ -1131,7 +1131,7 @@ static vm_fault_t vm_fault_ttm(struct vm_fault *vmf)
 		GEM_WARN_ON(!i915_ttm_cpu_maps_iomem(bo->resource));
 	}
 
-	if (wakeref & CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND)
+	if (wakeref && CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND != 0)
 		intel_wakeref_auto(&to_i915(obj->base.dev)->runtime_pm.userfault_wakeref,
 				   msecs_to_jiffies_timeout(CONFIG_DRM_I915_USERFAULT_AUTOSUSPEND));
 
-- 
2.39.2



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