drm/amdgpu: fix aperture iounmap skipped on device removal

amdgpu_pci_remove() calls drm_dev_unplug() before invoking the fini
routines. After drm_dev_unplug() the drm_dev_enter() guard in
amdgpu_ttm_fini() always returns false, so iounmap() for
aper_base_kaddr is silently skipped. On connected_to_cpu hardware
ioremap_cache() maps the aperture as WB; when iounmap() is skipped the
stale WB PAT entry persists. On reload IP discovery's
memremap(MEMREMAP_WC) on the same aperture range hits a WB/WC conflict,
producing an ioremap error and failing re-probe.

Remove the drm_dev_enter() guard and call iounmap() unconditionally.
The aperture mapping is plain MMIO and does not require device-presence
protection. Surprise-removal cleanup of aper_base_kaddr is already
handled unconditionally by amdgpu_device_unmap_mmio().

Fixes: 62d5f9f7110a ("drm/amdgpu: Unmap MMIO mappings when device is not unplugged")
Signed-off-by: Asad Kamal <asad.kamal@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Reviewed-by: Hawking Zhang <Hawking.Zhang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit fb3f68af9f6fce9343a2bd13b4d68a1c02d283df)
Cc: stable@vger.kernel.org

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 12a3b8bc58a4c9fc2863e9bbef61eec5abcec2ad..eaa86e32912e59912311894dee2da3eb6331b483 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -2259,8 +2259,6 @@ int amdgpu_ttm_init(struct amdgpu_device *adev)
  */
 void amdgpu_ttm_fini(struct amdgpu_device *adev)
 {
-       int idx;
-
        if (!adev->mman.initialized)
                return;
 
@@ -2283,13 +2281,9 @@ void amdgpu_ttm_fini(struct amdgpu_device *adev)
        amdgpu_ttm_unmark_vram_reserved(adev, AMDGPU_RESV_FW_VRAM_USAGE);
        amdgpu_ttm_unmark_vram_reserved(adev, AMDGPU_RESV_DRV_VRAM_USAGE);
 
-       if (drm_dev_enter(adev_to_drm(adev), &idx)) {
-
-               if (adev->mman.aper_base_kaddr)
-                       iounmap(adev->mman.aper_base_kaddr);
+       if (adev->mman.aper_base_kaddr) {
+               iounmap(adev->mman.aper_base_kaddr);
                adev->mman.aper_base_kaddr = NULL;
-
-               drm_dev_exit(idx);
        }
 
        if (!adev->gmc.is_app_apu)