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* [Intel-gfx] [PATCH] drm/i915/mtl: Fix MTL stolen memory GGTT mapping
@ 2023-03-28  1:24 Daniele Ceraolo Spurio
  2023-03-28  1:48 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for " Patchwork
                   ` (4 more replies)
  0 siblings, 5 replies; 6+ messages in thread
From: Daniele Ceraolo Spurio @ 2023-03-28  1:24 UTC (permalink / raw)
  To: intel-gfx; +Cc: Lucas De Marchi, dri-devel, Matt Roper, Nirmoy Das

The PTEs expect the offset from the base of the fake LMEM region (i.e.
the base of stolen) and not from the base of the DSM. Quoting the specs:
"Driver will set the Device Memory bit = 1 in the PTE when pointing to a
page in DSM and program the PTE with offset from LMEM_BAR. Device Memory
Offset from LMEM_BAR is same as offset from BGSM."

DSM starts 8MBs from BGSM, so we set dsm_base = 8MB.

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Aravind Iddamsetty <aravind.iddamsetty@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Nirmoy Das <nirmoy.das@intel.com>
Cc: Fei Yang <fei.yang@intel.com>
Cc: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
---

I've omitted the fixes tag from the commit message since MTL is still
under force_probe, so there isn't really any need to propagate the fixes,
but here it is for reference:

Fixes: dbb2ffbfd708 ("drm/i915/mtl: enable local stolen memory")

 drivers/gpu/drm/i915/gem/i915_gem_stolen.c | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
index d8e06e783e30..8ac376c24aa2 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_stolen.c
@@ -890,8 +890,9 @@ i915_gem_stolen_lmem_setup(struct drm_i915_private *i915, u16 type,
 	if (HAS_LMEMBAR_SMEM_STOLEN(i915)) {
 		/*
 		 * MTL dsm size is in GGC register.
-		 * Also MTL uses offset to DSMBASE in ptes, so i915
-		 * uses dsm_base = 0 to setup stolen region.
+		 * Also MTL uses offset to GSMBASE in ptes, so i915
+		 * uses dsm_base = 8MBs to setup stolen region, since
+		 * DSMBASE = GSMBASE + 8MB.
 		 */
 		ret = mtl_get_gms_size(uncore);
 		if (ret < 0) {
@@ -899,11 +900,11 @@ i915_gem_stolen_lmem_setup(struct drm_i915_private *i915, u16 type,
 			return ERR_PTR(ret);
 		}
 
-		dsm_base = 0;
+		dsm_base = SZ_8M;
 		dsm_size = (resource_size_t)(ret * SZ_1M);
 
 		GEM_BUG_ON(pci_resource_len(pdev, GEN12_LMEM_BAR) != SZ_256M);
-		GEM_BUG_ON((dsm_size + SZ_8M) > lmem_size);
+		GEM_BUG_ON((dsm_base + dsm_size) > lmem_size);
 	} else {
 		/* Use DSM base address instead for stolen memory */
 		dsm_base = intel_uncore_read64(uncore, GEN12_DSMBASE) & GEN12_BDSM_MASK;
@@ -912,14 +913,12 @@ i915_gem_stolen_lmem_setup(struct drm_i915_private *i915, u16 type,
 		dsm_size = ALIGN_DOWN(lmem_size - dsm_base, SZ_1M);
 	}
 
-	io_size = dsm_size;
-	if (HAS_LMEMBAR_SMEM_STOLEN(i915)) {
-		io_start = pci_resource_start(pdev, GEN12_LMEM_BAR) + SZ_8M;
-	} else if (pci_resource_len(pdev, GEN12_LMEM_BAR) < lmem_size) {
+	if (pci_resource_len(pdev, GEN12_LMEM_BAR) < lmem_size) {
 		io_start = 0;
 		io_size = 0;
 	} else {
 		io_start = pci_resource_start(pdev, GEN12_LMEM_BAR) + dsm_base;
+		io_size = dsm_size;
 	}
 
 	min_page_size = HAS_64K_PAGES(i915) ? I915_GTT_PAGE_SIZE_64K :
-- 
2.37.3


^ permalink raw reply related	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2023-03-28 12:05 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-03-28  1:24 [Intel-gfx] [PATCH] drm/i915/mtl: Fix MTL stolen memory GGTT mapping Daniele Ceraolo Spurio
2023-03-28  1:48 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for " Patchwork
2023-03-28  1:55 ` [Intel-gfx] ✓ Fi.CI.BAT: success " Patchwork
2023-03-28  9:29 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork
2023-03-28 10:07 ` [Intel-gfx] [PATCH] " Andi Shyti
2023-03-28 12:05 ` Das, Nirmoy

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