drm/xe/uapi: Add NO_COMPRESSION BO flag and query capability

Introduce DRM_XE_GEM_CREATE_FLAG_NO_COMPRESSION to let userspace
opt out of CCS compression on a per-BO basis. When set, the driver
maps this to XE_BO_FLAG_NO_COMPRESSION, skips CCS metadata
allocation/clearing, and rejects compressed PAT indices at vm_bind.
This avoids extra memory ops and manual CCS state handling for buffers.

To allow userspace to detect at runtime whether the kernel supports this
feature, add DRM_XE_QUERY_CONFIG_FLAG_HAS_NO_COMPRESSION_HINT and expose
it via query_config() on Xe2+ platforms.

Mesa PR: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/38425
IGT PR: https://patchwork.freedesktop.org/patch/685180/

v2
- Changed error code from -EINVAL to -EOPNOTSUPP for unsupported flag
  usage on pre-Xe2 platforms
- Fixed checkpatch warning in xe_vm.c
- Fixed kernel-doc formatting in xe_drm.h

v3
- Rebase
- Updated commit title and description
- Added UAPI for DRM_XE_QUERY_CONFIG_FLAG_HAS_NO_COMPRESSION_HINT and
  exposed it via query_config()

v4
- Rebase

v5
- Included Mesa PR and IGT PR in the commit description
- Used xe_pat_index_get_comp_en() to extract the compression

v6
- Added XE_IOCTL_DBG() checks for argument validation

Suggested-by: Matthew Auld <matthew.auld@intel.com>
Suggested-by: José Roberto de Souza <jose.souza@intel.com>
Acked-by: José Roberto de Souza <jose.souza@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Sanjay Yadav <sanjay.kumar.yadav@intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patch.msgid.link/20251204040402.2692921-2-sanjay.kumar.yadav@intel.com

1 files changed, 16 insertions, 0 deletions

diff --git a/include/uapi/drm/xe_drm.h b/include/uapi/drm/xe_drm.h
index 37881b1eb6ba..0d99bb0cd20a 100644
--- a/include/uapi/drm/xe_drm.h
+++ b/include/uapi/drm/xe_drm.h
@@ -407,6 +407,9 @@ struct drm_xe_query_mem_regions {
  *      has low latency hint support
  *    - %DRM_XE_QUERY_CONFIG_FLAG_HAS_CPU_ADDR_MIRROR - Flag is set if the
  *      device has CPU address mirroring support
+ *    - %DRM_XE_QUERY_CONFIG_FLAG_HAS_NO_COMPRESSION_HINT - Flag is set if the
+ *      device supports the userspace hint %DRM_XE_GEM_CREATE_FLAG_NO_COMPRESSION.
+ *      This is exposed only on Xe2+.
  *  - %DRM_XE_QUERY_CONFIG_MIN_ALIGNMENT - Minimal memory alignment
  *    required by this device, typically SZ_4K or SZ_64K
  *  - %DRM_XE_QUERY_CONFIG_VA_BITS - Maximum bits of a virtual address
@@ -425,6 +428,7 @@ struct drm_xe_query_config {
 	#define DRM_XE_QUERY_CONFIG_FLAG_HAS_VRAM	(1 << 0)
 	#define DRM_XE_QUERY_CONFIG_FLAG_HAS_LOW_LATENCY	(1 << 1)
 	#define DRM_XE_QUERY_CONFIG_FLAG_HAS_CPU_ADDR_MIRROR	(1 << 2)
+	#define DRM_XE_QUERY_CONFIG_FLAG_HAS_NO_COMPRESSION_HINT (1 << 3)
 #define DRM_XE_QUERY_CONFIG_MIN_ALIGNMENT		2
 #define DRM_XE_QUERY_CONFIG_VA_BITS			3
 #define DRM_XE_QUERY_CONFIG_MAX_EXEC_QUEUE_PRIORITY	4
@@ -795,6 +799,17 @@ struct drm_xe_device_query {
  *    need to use VRAM for display surfaces, therefore the kernel requires
  *    setting this flag for such objects, otherwise an error is thrown on
  *    small-bar systems.
+ *  - %DRM_XE_GEM_CREATE_FLAG_NO_COMPRESSION - Allows userspace to
+ *    hint that compression (CCS) should be disabled for the buffer being
+ *    created. This can avoid unnecessary memory operations and CCS state
+ *    management.
+ *    On pre-Xe2 platforms, this flag is currently rejected as compression
+ *    control is not supported via PAT index. On Xe2+ platforms, compression
+ *    is controlled via PAT entries. If this flag is set, the driver will reject
+ *    any VM bind that requests a PAT index enabling compression for this BO.
+ *    Note: On dGPU platforms, there is currently no change in behavior with
+ *    this flag, but future improvements may leverage it. The current benefit is
+ *    primarily applicable to iGPU platforms.
  *
  * @cpu_caching supports the following values:
  *  - %DRM_XE_GEM_CPU_CACHING_WB - Allocate the pages with write-back
@@ -841,6 +856,7 @@ struct drm_xe_gem_create {
 #define DRM_XE_GEM_CREATE_FLAG_DEFER_BACKING		(1 << 0)
 #define DRM_XE_GEM_CREATE_FLAG_SCANOUT			(1 << 1)
 #define DRM_XE_GEM_CREATE_FLAG_NEEDS_VISIBLE_VRAM	(1 << 2)
+#define DRM_XE_GEM_CREATE_FLAG_NO_COMPRESSION		(1 << 3)
 	/**
 	 * @flags: Flags, currently a mask of memory instances of where BO can
 	 * be placed