linux.git/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c, branch v7.1-rc5 Linux kernel source tree drm/amdgpu: fix zero-size GDS range init on RDNA4 2026-04-24T15:07:53+00:00 Arjan van de Ven arjan@linux.intel.com 2026-04-20T21:57:15+00:00 095a8b0ad3c3b5cdc3850d961adb8a8f735220bb RDNA4 (GFX 12) hardware removes the GDS, GWS, and OA on-chip memory resources. The gfx_v12_0 initialisation code correctly leaves adev->gds.gds_size, adev->gds.gws_size, and adev->gds.oa_size at zero to reflect this. amdgpu_ttm_init() unconditionally calls amdgpu_ttm_init_on_chip() for each of these resources regardless of size. When the size is zero, amdgpu_ttm_init_on_chip() forwards the call to ttm_range_man_init(), which calls drm_mm_init(mm, 0, 0). drm_mm_init() immediately fires DRM_MM_BUG_ON(start + size <= start) -- trivially true when size is zero -- crashing the kernel during modprobe of amdgpu on an RX 9070 XT. Guard against this by returning 0 early from amdgpu_ttm_init_on_chip() when size_in_page is zero. This skips TTM resource manager registration for hardware resources that are absent, without affecting any other GPU type. DRM_MM_BUG_ON() only asserts if CONFIG_DRM_DEBUG_MM is enabled in the kernel config. This is apparently rarely enabled as these chips have been in the market for over a year and this issue was only reported now. Link: https://lore.kernel.org/all/bug-221376-2300@https.bugzilla.kernel.org%2F/ Link: https://bugzilla.kernel.org/show_bug.cgi?id=221376 Oops-Analysis: http://oops.fenrus.org/reports/bugzilla.korg/221376/report.html Assisted-by: GitHub Copilot:Claude Sonnet 4.6 linux-kernel-oops-x86. Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: "Christian König" <christian.koenig@amd.com> Cc: amd-gfx@lists.freedesktop.org Cc: dri-devel@lists.freedesktop.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Alex Deucher <alexander.deucher@amd.com> (cherry picked from commit 5719ce5865279cad4fd5f01011fe037168503f2d) Cc: stable@vger.kernel.org 
RDNA4 (GFX 12) hardware removes the GDS, GWS, and OA on-chip memory
resources. The gfx_v12_0 initialisation code correctly leaves
adev->gds.gds_size, adev->gds.gws_size, and adev->gds.oa_size at
zero to reflect this.

amdgpu_ttm_init() unconditionally calls amdgpu_ttm_init_on_chip() for
each of these resources regardless of size. When the size is zero,
amdgpu_ttm_init_on_chip() forwards the call to ttm_range_man_init(),
which calls drm_mm_init(mm, 0, 0). drm_mm_init() immediately fires
DRM_MM_BUG_ON(start + size <= start) -- trivially true when size is
zero -- crashing the kernel during modprobe of amdgpu on an RX 9070 XT.

Guard against this by returning 0 early from
amdgpu_ttm_init_on_chip() when size_in_page is zero. This skips TTM
resource manager registration for hardware resources that are absent,
without affecting any other GPU type.

DRM_MM_BUG_ON() only asserts if CONFIG_DRM_DEBUG_MM is enabled in
the kernel config.  This is apparently rarely enabled as these chips
have been in the market for over a year and this issue was only reported
now.

Link: https://lore.kernel.org/all/bug-221376-2300@https.bugzilla.kernel.org%2F/
Link: https://bugzilla.kernel.org/show_bug.cgi?id=221376
Oops-Analysis: http://oops.fenrus.org/reports/bugzilla.korg/221376/report.html
Assisted-by: GitHub Copilot:Claude Sonnet 4.6 linux-kernel-oops-x86.
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 5719ce5865279cad4fd5f01011fe037168503f2d)
Cc: stable@vger.kernel.org
drm/amdgpu: Consolidate reserve region allocations 2026-04-03T17:50:26+00:00 Lijo Lazar lijo.lazar@amd.com 2026-03-26T05:51:15+00:00 f315099fd26ae8e9ab7718fbc8f66b157828313a Move marking reserve regions to a single function. It loops through all the reserve region ids. The ones with non-zero size are reserved. There are still some reservations which could happen later during runtime like firmware extended reservation region. Signed-off-by: Lijo Lazar <lijo.lazar@amd.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> 
Move marking reserve regions to a single function. It loops through all
the reserve region ids. The ones with non-zero size are reserved. There
are still some reservations which could happen later during runtime like
firmware extended reservation region.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
drm/amdgpu: Move validation of reserve region info 2026-04-03T17:50:20+00:00 Lijo Lazar lijo.lazar@amd.com 2026-03-26T05:41:39+00:00 6845355a08c2dc7e5af3c37b7d8f61afbfec1939 Keep validation of reserved regions also as part of filling details. If the information is invalid, size is kept as 0 so that it's not considered for reservation. Signed-off-by: Lijo Lazar <lijo.lazar@amd.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> 
Keep validation of reserved regions also as part of filling details. If
the information is invalid, size is kept as 0 so that it's not
considered for reservation.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
drm/amdgpu: Add function to fill training region 2026-04-03T17:50:17+00:00 Lijo Lazar lijo.lazar@amd.com 2026-03-26T05:36:10+00:00 7b0af16044b7669685f923d2c83c20d3aba72e18 Add a function to fill in memory training reservation region. Only if the reservation for the region is successful, memory training context will be initialized. Signed-off-by: Lijo Lazar <lijo.lazar@amd.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> 
Add a function to fill in memory training reservation region. Only if
the reservation for the region is successful, memory training context
will be initialized.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
drm/amdgpu: Add function to fill fw reserve region 2026-04-03T17:50:13+00:00 Lijo Lazar lijo.lazar@amd.com 2026-03-26T05:24:38+00:00 2c7b0e37835cc4522debba57b31b491025e9728c Add a function to fill in details for firmware reserve region. Signed-off-by: Lijo Lazar <lijo.lazar@amd.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> 
Add a function to fill in details for firmware reserve region.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
drm/amdgpu: Group filling reserve region details 2026-04-03T17:50:09+00:00 Lijo Lazar lijo.lazar@amd.com 2026-03-26T05:09:16+00:00 5dad4394229953cae4e040107a4fd1886dc01f30 Add a function which groups filling of reserve region information. It may not cover all as info on some regions are still filled outside like those from atomfirmware tables. Signed-off-by: Lijo Lazar <lijo.lazar@amd.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> 
Add a function which groups filling of reserve region information. It
may not cover all as info on some regions are still filled outside like
those from atomfirmware tables.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
drm/amdgpu: Add memory training reserve-region 2026-04-03T17:50:04+00:00 Lijo Lazar lijo.lazar@amd.com 2026-03-25T13:40:16+00:00 bb92be605290d11b5bab307f76ab85013beba847 Use reserve region helpers for initializing/reserving memory training region. Signed-off-by: Lijo Lazar <lijo.lazar@amd.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> 
Use reserve region helpers for initializing/reserving memory training
region.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
drm/amdgpu: Add host driver reserved-region 2026-04-03T17:50:01+00:00 Lijo Lazar lijo.lazar@amd.com 2026-03-25T13:10:24+00:00 4c616e8446b916d8888415c76a91b36a00f94f79 Use reserve region helpers for initializing/reserving host driver reserved region in virtualization environment. Signed-off-by: Lijo Lazar <lijo.lazar@amd.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> 
Use reserve region helpers for initializing/reserving host driver
reserved region in virtualization environment.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
drm/amdgpu: Add fw vram usage reserve-region 2026-04-03T17:49:58+00:00 Lijo Lazar lijo.lazar@amd.com 2026-03-25T13:02:25+00:00 daaf24d1fc538fc713ffc4a84949af0d92f06fb4 Use reserve region helpers for initializing/reserving firmware usage region in virtualized environments. Signed-off-by: Lijo Lazar <lijo.lazar@amd.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> 
Use reserve region helpers for initializing/reserving firmware usage
region in virtualized environments.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
drm/amdgpu: Add firmware extended reserve-region 2026-04-03T17:49:49+00:00 Lijo Lazar lijo.lazar@amd.com 2026-03-25T11:50:11+00:00 14a517e37a575da79681c9b5e3b39d3755cbd94d Use reserve region helpers for initializing/reserving extended firmware reservation area. Signed-off-by: Lijo Lazar <lijo.lazar@amd.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> 
Use reserve region helpers for initializing/reserving extended firmware
reservation area.

Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>