From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lorenzo Pieralisi Subject: Re: [PATCH V4 3/4] ACPI/IORT: Ignore all errors except EPROBE_DEFER Date: Mon, 22 May 2017 11:37:31 +0100 Message-ID: <20170522103730.GB7553@red-moon> References: <1495119257-26724-1-git-send-email-sricharan@codeaurora.org> <1495119257-26724-3-git-send-email-sricharan@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1495119257-26724-3-git-send-email-sricharan@codeaurora.org> Sender: linux-acpi-owner@vger.kernel.org To: Sricharan R Cc: robin.murphy@arm.com, will.deacon@arm.com, joro@8bytes.org, iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, m.szyprowski@samsung.com, bhelgaas@google.com, linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org, tn@semihalf.com, hanjun.guo@linaro.org, okaya@codeaurora.org, robh+dt@kernel.org, frowand.list@gmail.com, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, sudeep.holla@arm.com, rjw@rjwysocki.net, lenb@kernel.org, catalin.marinas@arm.com, arnd@arndb.de, linux-arch@vger.kernel.org, laurent.pinchart@ideasonboard.com, j.neuschaefer@gmx.net, geert@linux-m68k.org, magnus.damm@gmail.com List-Id: devicetree@vger.kernel.org Hi Sricharan, On Thu, May 18, 2017 at 08:24:16PM +0530, Sricharan R wrote: > While deferring the probe of IOMMU masters, xlate and > add_device callbacks called from iort_iommu_configure > can pass back error values like -ENODEV, which means > the IOMMU cannot be connected with that master for real > reasons. Before the IOMMU probe deferral, all such errors > were ignored. Now all those errors are propagated back, > killing the master's probe for such errors. Instead ignore > all the errors except EPROBE_DEFER, which is the only one > of concern and let the master work without IOMMU, thus > restoring the old behavior. > > Fixes: 5a1bb638d567 ("drivers: acpi: Handle IOMMU lookup failure with deferred probing or error") > Signed-off-by: Sricharan R > --- > [V4] Added this patch newly. > > drivers/acpi/arm64/iort.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c > index c5fecf9..16e101f 100644 > --- a/drivers/acpi/arm64/iort.c > +++ b/drivers/acpi/arm64/iort.c > @@ -782,6 +782,12 @@ const struct iommu_ops *iort_iommu_configure(struct device *dev) > if (err) > ops = ERR_PTR(err); > > + /* Ignore all other errors apart from EPROBE_DEFER */ > + if (IS_ERR(ops) && (PTR_ERR(ops) != -EPROBE_DEFER)) { > + dev_dbg(dev, "Adding to IOMMU failed: %ld\n", PTR_ERR(ops)); > + ops = NULL; > + } > + > return ops; > } > It is getting a bit convoluted. Is not it better to propagate the error back and let acpi_dma_configure() make a decision accordingly ? Something like: -- >8 -- diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index e39ec7b..3a10d757 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -1371,8 +1371,8 @@ int acpi_dma_configure(struct device *dev, enum dev_dma_attr attr) iort_set_dma_mask(dev); iommu = iort_iommu_configure(dev); - if (IS_ERR(iommu)) - return PTR_ERR(iommu); + if (IS_ERR(iommu) && PTR_ERR(iommu) == -EPROBE_DEFER) + return -EPROBE_DEFER; size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1); /*