For this series: Reviewed-by: Christian König <christian.koenig at amd.com>
Am 22.12.2014 um 12:07 schrieb Oded Gabbay: > This small patch-set, was created to solve the bug described at > https://bugzilla.kernel.org/show_bug.cgi?id=89661 (Kernel panic when > trying use amdkfd driver on Kaveri). It replaces the previous patch-set called > [PATCH 0/3] Use workqueue for device init in amdkfd > (http://lists.freedesktop.org/archives/dri-devel/2014-December/074401.html) > > That bug appears only when radeon, amdkfd and amd_iommu_v2 are compiled > inside the kernel (not as modules). In that case, the correct loading > order, as determined by the exported symbol used by each driver, is > not enforced anymore and the kernel loads them based on who was linked > first. That makes radeon load first, amdkfd second and amd_iommu_v2 > third. > > Because the initialization of a device in amdkfd is initiated by radeon, > and can only be completed if amdkfd and amd_iommu_v2 were loaded and > initialized, then in the case mentioned above, this initalization fails > and there is a kernel panic as some pointers are not initialized but > used nontheless. > > To solve this bug, this patch-set moves iommu/ before gpu/ in drivers/Makefile > and also moves amdkfd/ before radeon/ in drivers/gpu/drm/Makefile. > > The rationale is that in general, AMD GPU devices are dependent on AMD IOMMU > controller functionality to allow the GPU to access a process's virtual memory > address space, without the need for pinning the memory. That's why it makes > sense to initialize the iommu/ subsystem ahead of the gpu/ subsystem. > > Oded > > Oded Gabbay (2): > drivers: Move iommu/ before gpu/ in Makefile > drm: Put amdkfd before radeon in drm Makefile > > drivers/Makefile | 6 ++++-- > drivers/gpu/drm/Makefile | 2 +- > 2 files changed, 5 insertions(+), 3 deletions(-) >
