From: Imre Deak <imre.deak@xxxxxxxxx>
On DG1 A0/B0 steppings the first 1MB of local memory must be reserved.
One reason for this is that the 0xA0000-0xB0000 range is not accessible
by the display, probably since this region is redirected to another
memory location for legacy VGA compatibility.
BSpec: 50586
Testcase: igt/kms_big_fb/linear-64bpp-rotate-0
v2:
- Reserve the memory on B0 as well.
v3: replace DRM_DEBUG/DRM_ERROR with drm_dbg/drm_err
v4: fix the insanity
Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx>
Signed-off-by: Matthew Auld <matthew.auld@xxxxxxxxx>
---
drivers/gpu/drm/i915/gt/intel_region_lmem.c | 45 +++++++++++++++++++++
1 file changed, 45 insertions(+)
diff --git a/drivers/gpu/drm/i915/gt/intel_region_lmem.c b/drivers/gpu/drm/i915/gt/intel_region_lmem.c
index 71bb38706dbf..763b21980d74 100644
--- a/drivers/gpu/drm/i915/gt/intel_region_lmem.c
+++ b/drivers/gpu/drm/i915/gt/intel_region_lmem.c
@@ -143,6 +143,41 @@ intel_gt_setup_fake_lmem(struct intel_gt *gt)
return mem;
}
+static bool get_legacy_lowmem_region(struct intel_uncore *uncore,
+ u64 *start, u32 *size)
+{
+ if (!IS_DG1_REVID(uncore->i915, DG1_REVID_A0, DG1_REVID_B0))
+ return false;
+
+ *start = 0;
+ *size = SZ_1M;
+
+ drm_dbg(&uncore->i915->drm, "LMEM: reserved legacy low-memory [0x%llx-0x%llx]\n",
+ *start, *start + *size);
+
+ return true;
+}
+
+static int reserve_lowmem_region(struct intel_uncore *uncore,
+ struct intel_memory_region *mem)
+{
+ u64 reserve_start;
+ u32 reserve_size;
+ int ret;
+
+ if (!get_legacy_lowmem_region(uncore, &reserve_start, &reserve_size))
+ return 0;
+
+ if (!reserve_size)
+ return 0;
+
+ ret = intel_memory_region_reserve(mem, reserve_start, reserve_size);
+ if (ret)
+ drm_err(&uncore->i915->drm, "LMEM: reserving low memory region failed\n");
+
+ return ret;
+}
+
static struct intel_memory_region *setup_lmem(struct intel_gt *gt)
{
struct drm_i915_private *i915 = gt->i915;
@@ -167,6 +202,16 @@ static struct intel_memory_region *setup_lmem(struct intel_gt *gt)
I915_GTT_PAGE_SIZE_4K,
io_start,
&intel_region_lmem_ops);
+ if (!IS_ERR(mem)) {
+ int err;
+
+ err = reserve_lowmem_region(uncore, mem);
+ if (err) {
+ intel_memory_region_put(mem);
+ return ERR_PTR(err);
+ }
+ }
+
if (!IS_ERR(mem)) {
drm_dbg(&i915->drm, "Local memory: %pR\n", &mem->region);
drm_dbg(&i915->drm, "Local memory IO start: %pa\n",
--
2.26.2
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