Quoting Matthew Auld (2020-11-27 12:06:34)
From: Imre Deak imre.deak@intel.com
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 Signed-off-by: Imre Deak imre.deak@intel.com
drivers/gpu/drm/i915/intel_region_lmem.c | 52 ++++++++++++++++++++++++ 1 file changed, 52 insertions(+)
diff --git a/drivers/gpu/drm/i915/intel_region_lmem.c b/drivers/gpu/drm/i915/intel_region_lmem.c index 939cf0d195a5..eafef7034680 100644 --- a/drivers/gpu/drm/i915/intel_region_lmem.c +++ b/drivers/gpu/drm/i915/intel_region_lmem.c @@ -137,6 +137,48 @@ intel_setup_fake_lmem(struct drm_i915_private *i915) return mem; }
+static void get_legacy_lowmem_region(struct intel_uncore *uncore,
u64 *start, u32 *size)+{
*start = 0;*size = 0;if (!IS_DG1_REVID(uncore->i915, DG1_REVID_A0, DG1_REVID_B0))return;*size = SZ_1M;DRM_DEBUG_DRIVER("LMEM: reserved legacy low-memory [0x%llx-0x%llx]\n",*start, *start + *size);+}
+static int reserve_lowmem_region(struct intel_uncore *uncore,
struct intel_memory_region *mem)+{
u64 reserve_start;u64 reserve_end;u64 region_start;u32 region_size;int ret;get_legacy_lowmem_region(uncore, ®ion_start, ®ion_size);reserve_start = region_start;reserve_end = region_start + region_size;if (!reserve_end)return 0;DRM_INFO("LMEM: reserving low-memory region [0x%llx-0x%llx]\n",reserve_start, reserve_end);ret = i915_buddy_alloc_range(&mem->mm, &mem->reserved,reserve_start,reserve_end - reserve_start);
Isn't this now relative to the stolen offset? Should this be reserved, or excluded like stolen? -Chris