[PATCH v2 12/15] drm/xe/ttm: Reject VRAM allocations on wedged devices

[Arvind Yadav <arvind.yadav@intel.com>]

VRAM is no longer usable after the device is wedged. Reject observed
VRAM allocations with -ENODEV and stop placement fallback.

An allocation racing with the wedge may still complete. The wedged fault
path prevents new VRAM CPU mappings, and device teardown releases the
resource.

v2:
 - Return -ENODEV to stop placement fallback after a permanent wedge.
   (Rodrigo)

Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Thomas Hellström <thomas.hellstrom@linux.intel.com>
Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Assisted-by: Claude:claude-opus-4-8
Signed-off-by: Arvind Yadav <arvind.yadav@intel.com>
---
 drivers/gpu/drm/xe/xe_ttm_vram_mgr.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
index 9a514d983e90..088a690067b9 100644
--- a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
+++ b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
@@ -105,6 +105,7 @@ static int xe_ttm_vram_mgr_new(struct ttm_resource_manager *man,
 			       const struct ttm_place *place,
 			       struct ttm_resource **res)
 {
+	struct xe_device *xe = ttm_to_xe_device(tbo->bdev);
 	struct xe_ttm_vram_mgr *mgr = to_xe_ttm_vram_mgr(man);
 	struct xe_ttm_vram_mgr_resource *vres;
 	struct gpu_buddy *mm = &mgr->mm;
@@ -112,6 +113,9 @@ static int xe_ttm_vram_mgr_new(struct ttm_resource_manager *man,
 	unsigned long lpfn;
 	int err;
 
+	if (xe_device_wedged(xe))
+		return -ENODEV;
+
 	lpfn = place->lpfn;
 	if (!lpfn || lpfn > man->size >> PAGE_SHIFT)
 		lpfn = man->size >> PAGE_SHIFT;
-- 
2.43.0