[Intel-gfx] [PATCH] drm/i915: Check stolen memory size before calling drm_mm_init

[José Roberto de Souza]

From: Steve Carbonari <steven.carbon...@intel.com>

Add check for zero usable stolen memory before calling drm_mm_init
to support configurations where stolen memory exists but is fully
reserved.

Also skip memory test in such case.

Cc: Ville Syrjälä <ville.syrj...@linux.intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospu...@intel.com>
Signed-off-by: José Roberto de Souza <jose.so...@intel.com>
Signed-off-by: Steve Carbonari <steven.carbon...@intel.com>
---
 drivers/gpu/drm/i915/gem/i915_gem_stolen.c | 9 ++++++---
 drivers/gpu/drm/i915/intel_memory_region.c | 5 +++++
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c 
b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
index 1de73a6449652..98789a11cb413 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
@@ -496,13 +496,16 @@ static int i915_gem_init_stolen(struct 
intel_memory_region *mem)
         * memory, so just consider the start. */
        reserved_total = stolen_top - reserved_base;
 
+       i915->stolen_usable_size =
+               resource_size(&i915->dsm) - reserved_total;
+
        drm_dbg(&i915->drm,
                "Memory reserved for graphics device: %lluK, usable: %lluK\n",
                (u64)resource_size(&i915->dsm) >> 10,
-               ((u64)resource_size(&i915->dsm) - reserved_total) >> 10);
+               i915->stolen_usable_size >> 10);
 
-       i915->stolen_usable_size =
-               resource_size(&i915->dsm) - reserved_total;
+       if (i915->stolen_usable_size == 0)
+               return 0;
 
        /* Basic memrange allocator for stolen space. */
        drm_mm_init(&i915->mm.stolen, 0, i915->stolen_usable_size);
diff --git a/drivers/gpu/drm/i915/intel_memory_region.c 
b/drivers/gpu/drm/i915/intel_memory_region.c
index c70d7e286a512..329f46f71cdce 100644
--- a/drivers/gpu/drm/i915/intel_memory_region.c
+++ b/drivers/gpu/drm/i915/intel_memory_region.c
@@ -205,6 +205,11 @@ static int intel_memory_region_memtest(struct 
intel_memory_region *mem,
        if (!mem->io_start)
                return 0;
 
+       if ((mem->type == INTEL_MEMORY_STOLEN_LOCAL ||
+            mem->type == INTEL_MEMORY_STOLEN_SYSTEM) &&
+           !drm_mm_initialized(&i915->mm.stolen))
+               return 0;
+
        if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM) || i915->params.memtest)
                err = iomemtest(mem, i915->params.memtest, caller);
 
-- 
2.35.1