[PATCH v2 2/2] drm/xe: Remove bad VRAM pages debugfs interface

[Aravind Iddamsetty <aravind.iddamsetty@linux.intel.com>]

Drop the "vram_bad_pages" debugfs file added by commit fb19798cc366e
("drm/xe: Expose bad VRAM pages via debugfs"). The retired VRAM pages
are now exported through the drm-ras generic netlink interface, which
is a stable ABI, making the debugfs-only readback redundant.

This is a partial revert of fb19798cc366e: it removes vram_bad_pages_show(),
its DEFINE_SHOW_ATTRIBUTE(), xe_ttm_vram_debugfs_init() and its call site
and declaration, and the now-unused <linux/debugfs.h> include in
xe_ttm_vram_mgr.c. The struct xe_ttm_vram_mgr.max_pages field introduced
by the same commit is intentionally retained: it is the FW-provided
offline-page limit and is now consumed by the drm-ras retired-resources
capacity summary (xe_ttm_vram_get_max_bad_pages()).

The fault-injection debugfs interface (inject_mempage_offline) is left
untouched; it remains the mechanism for triggering page offlining in
test.

Cc: Tejas Upadhyay <tejas.upadhyay@intel.com>
Signed-off-by: Aravind Iddamsetty <aravind.iddamsetty@linux.intel.com>
Assisted-by: Copilot:claude-opus-4.8
---
 drivers/gpu/drm/xe/xe_debugfs.c      |  2 -
 drivers/gpu/drm/xe/xe_ttm_vram_mgr.c | 71 ----------------------------
 drivers/gpu/drm/xe/xe_ttm_vram_mgr.h |  1 -
 3 files changed, 74 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_debugfs.c b/drivers/gpu/drm/xe/xe_debugfs.c
index 926020c7526e..6a19737104fb 100644
--- a/drivers/gpu/drm/xe/xe_debugfs.c
+++ b/drivers/gpu/drm/xe/xe_debugfs.c
@@ -823,8 +823,6 @@ void xe_debugfs_register(struct xe_device *xe)
 	if (man)
 		ttm_resource_manager_create_debugfs(man, root, "stolen_mm");
 
-	xe_ttm_vram_debugfs_init(xe, root);
-
 	for_each_tile(tile, xe, tile_id)
 		xe_tile_debugfs_register(tile);
 
diff --git a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
index b56b543a56a2..9fbdf1dcde8a 100644
--- a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
+++ b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.c
@@ -5,7 +5,6 @@
  */
 
 #include <linux/cgroup_dmem.h>
-#include <linux/debugfs.h>
 
 #include <drm/drm_managed.h>
 #include <drm/drm_drv.h>
@@ -1120,73 +1119,3 @@ int xe_ttm_vram_inject_fault(struct xe_device *xe)
 	return -ENOSPC;
 }
 EXPORT_SYMBOL(xe_ttm_vram_inject_fault);
-
-static int vram_bad_pages_show(struct seq_file *m, void *unused)
-{
-	struct xe_device *xe = m->private;
-	struct xe_ttm_vram_offline_resource *pos;
-	struct ttm_resource_manager *man;
-	struct xe_ttm_vram_mgr *mgr;
-	struct xe_tile *tile;
-	u8 id;
-
-	man = ttm_manager_type(&xe->ttm, XE_PL_VRAM0);
-	if (man)
-		/* TODO Hook with RAS to show max_pages fetched from FW */
-		seq_printf(m, "max_pages: %d\n",
-			   to_xe_ttm_vram_mgr(man)->max_pages);
-
-	for_each_tile(tile, xe, id) {
-		struct xe_vram_region *vr = tile->mem.vram;
-
-		man = ttm_manager_type(&xe->ttm, XE_PL_VRAM0 + id);
-		if (!man || !vr)
-			continue;
-		mgr = to_xe_ttm_vram_mgr(man);
-
-		rcu_read_lock();
-
-		list_for_each_entry_rcu(pos, &mgr->offlined_pages, offlined_link) {
-			u64 pfn;
-
-			pfn = (pos->addr + vr->dpa_base) >> PAGE_SHIFT;
-			seq_printf(m, "0x%016llx : 0x%016lx : R\n", pfn, PAGE_SIZE);
-		}
-
-		list_for_each_entry_rcu(pos, &mgr->queued_pages, queued_link) {
-			u64 pfn;
-
-			pfn = (pos->addr + vr->dpa_base) >> PAGE_SHIFT;
-			seq_printf(m, "0x%016llx : 0x%016lx : %c\n",
-				   pfn, PAGE_SIZE, pos->status ? 'F' : 'P');
-		}
-
-		rcu_read_unlock();
-	}
-
-	return 0;
-}
-DEFINE_SHOW_ATTRIBUTE(vram_bad_pages);
-
-/**
- * xe_ttm_vram_debugfs_init - Initialize VRAM debugfs interfaces
- * @xe: The xe device structure pointer
- * @root: The root dentry of the debugfs directory
- *
- * This function registers platform-specific VRAM debugfs files used for
- * testing and debugging. Currently, it exposes the "vram_bad_pages" interface
- * to inspect marked faulty memory pages, restricted specifically to the
- * %XE_CRESCENTISLAND platform.
- *
- * Return: Void.
- */
-void xe_ttm_vram_debugfs_init(struct xe_device *xe, struct dentry *root)
-{
-	/*
-	 * TODO: Replace platform check with xe->info
-	 * once the feature flag is plumbed through device info.
-	 */
-	if (xe->info.platform != XE_CRESCENTISLAND)
-		return;
-	debugfs_create_file("vram_bad_pages", 0444, root, xe, &vram_bad_pages_fops);
-}
diff --git a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h
index 70fae023d6a3..7a4a041b8218 100644
--- a/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h
+++ b/drivers/gpu/drm/xe/xe_ttm_vram_mgr.h
@@ -17,7 +17,6 @@ int __xe_ttm_vram_mgr_init(struct xe_device *xe, struct xe_ttm_vram_mgr *mgr,
 			   u32 mem_type, u64 size, u64 io_size,
 			   u64 default_page_size);
 int xe_ttm_vram_mgr_init(struct xe_device *xe, struct xe_vram_region *vram);
-void xe_ttm_vram_debugfs_init(struct xe_device *xe, struct dentry *root);
 int xe_ttm_vram_mgr_alloc_sgt(struct xe_device *xe,
 			      struct ttm_resource *res,
 			      u64 offset, u64 length,
-- 
2.25.1