From mboxrd@z Thu Jan 1 00:00:00 1970 From: okaya@codeaurora.org (Sinan Kaya) Date: Tue, 14 Feb 2017 16:25:22 -0500 Subject: [PATCH 2/2] iommu: add warning when sharing groups In-Reply-To: <1487107522-8695-1-git-send-email-okaya@codeaurora.org> References: <1487107522-8695-1-git-send-email-okaya@codeaurora.org> Message-ID: <1487107522-8695-2-git-send-email-okaya@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org The ACS requirement has been obscured in the current code and is only known by certain individuals who happen to read the code. Print out a warning with ACS path failure when ACS requirement is not met. Signed-off-by: Sinan Kaya --- drivers/iommu/iommu.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index dbe7f65..049ee0a 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -811,6 +811,9 @@ struct iommu_group *pci_device_group(struct device *dev) if (IS_ERR(group)) return NULL; + if (pci_is_root_bus(bus)) + dev_warn_once(&pdev->dev, "using shared group due to ACS path failure\n"); + return group; } -- 1.9.1