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drm/panthor: Evict groups before VM termination

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Ensure all related groups are evicted and suspended before VM
destruction takes place.

This fixes an issue where panthor_vm_destroy() destroys and unmaps the
heap context while there are still on slot groups using this.
The FW will do a write out to the heap context when a CSG (group) is
suspended, so a premature unmap of the heap context will cause a
GPU page fault.
This page fault is quite harmless, and do not affect the continued
operation of the GPU.

Fixes: 647810ec24 ("drm/panthor: Add the MMU/VM logical block")
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Ketil Johnsen <ketil.johnsen@arm.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://patch.msgid.link/20251219093546.1227697-1-ketil.johnsen@arm.com
Co-developed-by: Boris Brezillon <boris.brezillon@collabora.com>
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
This commit is contained in:
Ketil Johnsen 2025-12-19 10:35:44 +01:00 committed by Boris Brezillon
parent 332070795b
commit 565ed40b5f
3 changed files with 19 additions and 0 deletions
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4
drivers/gpu/drm/panthor/panthor_mmu.c
View File

@ -1504,6 +1504,10 @@ static void panthor_vm_destroy(struct panthor_vm *vm)
vm->destroyed = true;
/* Tell scheduler to stop all GPU work related to this VM */
if (refcount_read(&vm->as.active_cnt) > 0)
panthor_sched_prepare_for_vm_destruction(vm->ptdev);
mutex_lock(&vm->heaps.lock);
panthor_heap_pool_destroy(vm->heaps.pool);
vm->heaps.pool = NULL;

14
drivers/gpu/drm/panthor/panthor_sched.c
View File

@ -2786,6 +2786,20 @@ void panthor_sched_report_mmu_fault(struct panthor_device *ptdev)
sched_queue_delayed_work(ptdev->scheduler, tick, 0);
}
void panthor_sched_prepare_for_vm_destruction(struct panthor_device *ptdev)
{
/* FW can write out internal state, like the heap context, during CSG
* suspend. It is therefore important that the scheduler has fully
* evicted any pending and related groups before VM destruction can
* safely continue. Failure to do so can lead to GPU page faults.
* A controlled termination of a Panthor instance involves destroying
* the group(s) before the VM. This means any relevant group eviction
* has already been initiated by this point, and we just need to
* ensure that any pending tick_work() has been completed.
*/
flush_work(&ptdev->scheduler->tick_work.work);
}
void panthor_sched_resume(struct panthor_device *ptdev)
{
/* Force a tick to re-evaluate after a resume. */

1
drivers/gpu/drm/panthor/panthor_sched.h
View File

@ -50,6 +50,7 @@ void panthor_sched_suspend(struct panthor_device *ptdev);
void panthor_sched_resume(struct panthor_device *ptdev);
void panthor_sched_report_mmu_fault(struct panthor_device *ptdev);
void panthor_sched_prepare_for_vm_destruction(struct panthor_device *ptdev);
void panthor_sched_report_fw_events(struct panthor_device *ptdev, u32 events);
void panthor_fdinfo_gather_group_samples(struct panthor_file *pfile);