From 09067207f6eacb7f00c8f7f0623c3696083ce042 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Mon, 15 Jun 2009 16:06:48 +0200 Subject: [PATCH] amd-iommu: set event buffer head and tail to 0 manually These registers may contain values from previous kernels. So reset them to known values before enable the event buffer again. Signed-off-by: Joerg Roedel --- arch/x86/kernel/amd_iommu_init.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/kernel/amd_iommu_init.c b/arch/x86/kernel/amd_iommu_init.c index 48a79b9b2f9e..068a3569f837 100644 --- a/arch/x86/kernel/amd_iommu_init.c +++ b/arch/x86/kernel/amd_iommu_init.c @@ -486,6 +486,10 @@ static void iommu_enable_event_buffer(struct amd_iommu *iommu) memcpy_toio(iommu->mmio_base + MMIO_EVT_BUF_OFFSET, &entry, sizeof(entry)); + /* set head and tail to zero manually */ + writel(0x00, iommu->mmio_base + MMIO_EVT_HEAD_OFFSET); + writel(0x00, iommu->mmio_base + MMIO_EVT_TAIL_OFFSET); + iommu_feature_enable(iommu, CONTROL_EVT_LOG_EN); } -- 2.39.5