Commit 276e4116 authored Dec 03, 2025 by Boris Brezillon Committed by Liviu Dudau Dec 03, 2025

drm/panthor: Unlock the locked region before disabling an AS



An AS can be disabled in the middle of a VM operation (VM being
evicted from an AS slot, for instance). In that case, we need the
locked section to be unlocked before releasing the slot.

v2:
- Add an lockdep_assert_held() in panthor_mmu_as_disable()
- Collect R-bs

v3:
- Don't reset the locked_region range in the as_disable() path

Fixes: 6e2d3b3e ("drm/panthor: Add support for atomic page table updates")
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Reviewed-by: Chia-I Wu <olvaffe@gmail.com>
Signed-off-by: Liviu Dudau <liviu.dudau@arm.com>
Link: https://patch.msgid.link/20251203121750.404340-4-boris.brezillon@collabora.com

parent 32e593d7

drivers/gpu/drm/panthor/panthor_mmu.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -588,14 +588,24 @@ static int panthor_mmu_as_enable(struct panthor_device *ptdev, u32 as_nr,
		static int panthor_mmu_as_disable(struct panthor_device *ptdev, u32 as_nr,
		bool recycle_slot)
		{
		struct panthor_vm *vm = ptdev->mmu->as.slots[as_nr].vm;
		int ret;

		lockdep_assert_held(&ptdev->mmu->as.slots_lock);

		/* Flush+invalidate RW caches, invalidate RO ones. */
		ret = panthor_gpu_flush_caches(ptdev, CACHE_CLEAN \| CACHE_INV,
		CACHE_CLEAN \| CACHE_INV, CACHE_INV);
		if (ret)
		return ret;

		if (vm && vm->locked_region.size) {
		/* Unlock the region if there's a lock pending. */
		ret = as_send_cmd_and_wait(ptdev, vm->as.id, AS_COMMAND_UNLOCK);
		if (ret)
		return ret;
		}

		/* If the slot is going to be used immediately, don't bother changing
		* the config.
		*/