[PATCH 8/8] x86/amd-iommu: Reset command buffer if wait loop fails

[Joerg Roedel <joerg.roedel@amd.com>]

Instead of a panic on an comletion wait loop failure, try to
recover from that event from resetting the command buffer.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
 arch/x86/kernel/amd_iommu.c |    7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index b62a2f6..cfca80b 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -318,8 +318,11 @@ static void __iommu_wait_for_completion(struct amd_iommu *iommu)
 	status &= ~MMIO_STATUS_COM_WAIT_INT_MASK;
 	writel(status, iommu->mmio_base + MMIO_STATUS_OFFSET);
 
-	if (unlikely(i == EXIT_LOOP_COUNT))
-		panic("AMD IOMMU: Completion wait loop failed\n");
+	if (unlikely(i == EXIT_LOOP_COUNT)) {
+		spin_unlock(&iommu->lock);
+		reset_iommu_command_buffer(iommu);
+		spin_lock(&iommu->lock);
+	}
 }
 
 /*
-- 
1.6.3.3