[PATCH] of: iommu: Silence misleading warning

[PATCH] of: iommu: Silence misleading warning

[Robin Murphy]

Printing "IOMMU is currently not supported for PCI" for every PCI device
probed on a DT-based system proves to be both irritatingly noisy and
confusing to users who have misinterpreted it to mean they can no longer
use VFIO device assignment.

Since configuring DMA masks for PCI devices via of_dma_configure() has
not in fact changed anything with regard to IOMMUs there really is nothing
to warn about here; shut it up.

Signed-off-by: Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>
---
 drivers/iommu/of_iommu.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/of_iommu.c b/drivers/iommu/of_iommu.c
index 43429ab..60ba238 100644
--- a/drivers/iommu/of_iommu.c
+++ b/drivers/iommu/of_iommu.c
@@ -141,10 +141,12 @@ struct iommu_ops *of_iommu_configure(struct device *dev,
 	struct iommu_ops *ops = NULL;
 	int idx = 0;
 
-	if (dev_is_pci(dev)) {
-		dev_err(dev, "IOMMU is currently not supported for PCI\n");
+	/*
+	 * We can't do much for PCI devices without knowing how
+	 * device IDs are wired up from the PCI bus to the IOMMU.
+	 */
+	if (dev_is_pci(dev))
 		return NULL;
-	}
 
 	/*
 	 * We don't currently walk up the tree looking for a parent IOMMU.
-- 
1.9.1

Re: [PATCH] of: iommu: Silence misleading warning

[Marc Zyngier]

On 22/07/15 18:47, Robin Murphy wrote:
> Printing "IOMMU is currently not supported for PCI" for every PCI device
> probed on a DT-based system proves to be both irritatingly noisy and
> confusing to users who have misinterpreted it to mean they can no longer
> use VFIO device assignment.
> 
> Since configuring DMA masks for PCI devices via of_dma_configure() has
> not in fact changed anything with regard to IOMMUs there really is nothing
> to warn about here; shut it up.
> 
> Signed-off-by: Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>

Ah, I was wondering why the kernel was shouting at me while everything
was indeed working just fine.

Acked-by: Marc Zyngier <marc.zyngier-5wv7dgnIgG8@public.gmane.org>

	M.
-- 
Jazz is not dead. It just smells funny...

Re: [PATCH] of: iommu: Silence misleading warning

[Joerg Roedel]

On Wed, Jul 22, 2015 at 06:47:00PM +0100, Robin Murphy wrote:
> Printing "IOMMU is currently not supported for PCI" for every PCI device
> probed on a DT-based system proves to be both irritatingly noisy and
> confusing to users who have misinterpreted it to mean they can no longer
> use VFIO device assignment.
> 
> Since configuring DMA masks for PCI devices via of_dma_configure() has
> not in fact changed anything with regard to IOMMUs there really is nothing
> to warn about here; shut it up.
> 
> Signed-off-by: Robin Murphy <robin.murphy-5wv7dgnIgG8@public.gmane.org>
> ---
>  drivers/iommu/of_iommu.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)

Applied, thanks.