Hi Lorenzo, On 5/22/2017 4:07 PM, Lorenzo Pieralisi wrote: > 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 <sricharan@xxxxxxxxxxxxxx> >> --- >> [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 ? > ok, I was trying to keep it in same way as DT, where of_dma_configure (here acpi_dma_configure) calls of_iommu_configure(here iort_iommu_configure) which ends up doing the check. So will have to be changed in both places for symmetry. > 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; In case of other errors apart from EPROBE_DEFER, iommu = NULL should be set, before passing it on to arch_setup_dma_ops. Regards, Sricharan > > size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1); > /* > -- "QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html