From mboxrd@z Thu Jan 1 00:00:00 1970 From: Olav Haugan Subject: Re: [PATCH 4/4] iommu/msm: Mark driver BROKEN Date: Wed, 04 Feb 2015 10:54:48 -0800 Message-ID: <54D26AF8.2010101@codeaurora.org> References: <1423036690-3862-1-git-send-email-thierry.reding@gmail.com> <1423036690-3862-5-git-send-email-thierry.reding@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii"; Format="flowed" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1423036690-3862-5-git-send-email-thierry.reding-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: iommu-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Thierry Reding , Joerg Roedel Cc: Nicolas Chauvet , Bryan Huntsman , iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Daniel Walker , David Brown List-Id: iommu@lists.linux-foundation.org Adding Mitch H. and Rob Clark. On 2/3/2015 11:58 PM, Thierry Reding wrote: > From: Thierry Reding > > The MSM IOMMU driver unconditionally calls bus_set_iommu(), which is a > very stupid thing to do on multi-platform kernels. While marking the > driver BROKEN may seem a little extreme, there is no other way to make > the driver skip initialization. One of the problems is that it doesn't > have devicetree binding documentation and the driver doesn't contain a > struct of_device_id table either, so no way to check that it is indeed > valid to set up the IOMMU operations for this driver. > > This fixes a problem on Tegra20 where the DRM driver will try to use the > obviously non-existent MSM IOMMU. > > Marking the driver BROKEN shouldn't do any harm, since there aren't any > users currently. There is no struct of_device_id table, so the device > can't be instantiated from device tree, and I couldn't find any code > that would instantiate a matching platform_device either, so the driver > is effectively unused. > > Reported-by: Nicolas Chauvet > Cc: David Brown > Cc: Daniel Walker > Cc: Bryan Huntsman > Cc: Olav Haugan > Signed-off-by: Thierry Reding > --- > drivers/iommu/Kconfig | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig > index 325188eef1c1..0f70bc1fce65 100644 > --- a/drivers/iommu/Kconfig > +++ b/drivers/iommu/Kconfig > @@ -31,6 +31,7 @@ config FSL_PAMU > config MSM_IOMMU > bool "MSM IOMMU Support" > depends on ARCH_MSM8X60 || ARCH_MSM8960 > + depends on BROKEN > select IOMMU_API > help > Support for the IOMMUs found on certain Qualcomm SOCs. > .Olav -- Qualcomm Innovation Center, Inc. The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project