[PATCH] nfit: add a module parameter to ignore ars errors

[Vishal Verma <vishal.l.verma@intel.com>]

Normally, if a platform does not advertise support for Address Range
Scrub (ARS), we skip it. But if ARS is advertised, it is expected to
always succeed. If it fails, we normally fail initialization at that
point.

Add a module parameter to nfit that lets it ignore ARS failures and
continue with initialization for debugging.

Signed-off-by: Vishal Verma <vishal.l.verma@intel.com>
---

This applies on top of both of the previous error handling series
(badblocks and libnvdimm poison list). The tree at:
https://git.kernel.org/cgit/linux/kernel/git/vishal/nvdimm.git/log/?h=err_handling_latest
has been updated with this patch.

 drivers/acpi/nfit.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c
index ad6d8c6..0a152f1 100644
--- a/drivers/acpi/nfit.c
+++ b/drivers/acpi/nfit.c
@@ -34,6 +34,10 @@ static bool force_enable_dimms;
 module_param(force_enable_dimms, bool, S_IRUGO|S_IWUSR);
 MODULE_PARM_DESC(force_enable_dimms, "Ignore _STA (ACPI DIMM device) status");
 
+static bool ignore_ars;
+module_param(ignore_ars, bool, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(ignore_ars, "Ignore ARS (Address Range Scrub) failures");
+
 struct nfit_table_prev {
 	struct list_head spas;
 	struct list_head memdevs;
@@ -1786,7 +1790,10 @@ static int acpi_nfit_register_region(struct acpi_nfit_desc *acpi_desc,
 			dev_err(acpi_desc->dev,
 				"error while performing ARS to find poison: %d\n",
 				rc);
-			return rc;
+			if (ignore_ars)
+				; /* continue initialization */
+			else
+				return rc;
 		}
 		if (!nvdimm_pmem_region_create(nvdimm_bus, ndr_desc))
 			return -ENOMEM;
-- 
2.5.0