From 9a5634a72934a566b3e5fdb0e8f345846162f7d3 Mon Sep 17 00:00:00 2001 From: Oded Gabbay Date: Mon, 17 Nov 2014 13:18:32 +0200 Subject: [PATCH] amdkfd: use schedule() in sync_with_hw amdkfd uses cpu_relax() in its sync_with_hw() function. Because cpu_relax() is defined as 'REP; NOP' on x86_64, it will block the CPU from servicing IOMMU PPR requests. This may cause a deadlock, because sync_with_hw() won't be completed until the PPR request has been served. Therefore, we need to use schedule() instead of cpu_relax() as it is the minimum requirement to allow other threads to execute. Reviewed-by: Alex Deucher Signed-off-by: Oded Gabbay --- drivers/gpu/drm/amd/amdkfd/kfd_kernel_queue.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_kernel_queue.c b/drivers/gpu/drm/amd/amdkfd/kfd_kernel_queue.c index 5055fc9c8731..9abac48de499 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_kernel_queue.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_kernel_queue.c @@ -25,6 +25,7 @@ #include #include #include +#include #include "kfd_kernel_queue.h" #include "kfd_priv.h" #include "kfd_device_queue_manager.h" @@ -274,7 +275,7 @@ static int sync_with_hw(struct kernel_queue *kq, unsigned long timeout_ms) *kq->wptr_kernel, *kq->rptr_kernel); return -ETIME; } - cpu_relax(); + schedule(); } return 0; -- 2.20.1