From a72255983f12f31f0c8d8275fb1a781546cfacb7 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Tue, 19 Jul 2016 12:32:39 -0700 Subject: [PATCH] nfit: make DIMM DSMs optional Commit 4995734e973a "acpi, nfit: fix acpi_check_dsm() vs zero functions implemented" attempted to fix a QEMU regression by supporting its usage of a zero-mask as a valid response to a DSM-family probe request. However, this behavior breaks HP platforms that return a zero-mask by default causing the probe to misidentify the DSM-family. Instead, the QEMU regression can be fixed by simply not requiring the DSM family to be identified. This effectively reverts commit 4995734e973a, and removes the DSM requirement from the init path. Cc: "Rafael J. Wysocki" Cc: Xiao Guangrong Cc: Linda Knippers Fixes: 4995734e973a ("acpi, nfit: fix acpi_check_dsm() vs zero functions implemented") Reported-by: Jerry Hoemann Tested-by: Jerry Hoemann Signed-off-by: Dan Williams --- drivers/acpi/nfit.c | 11 ++++++----- drivers/acpi/utils.c | 6 +++--- 2 files changed, 9 insertions(+), 8 deletions(-) diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c index ac6ddcc080d4..1f0e06065ae6 100644 --- a/drivers/acpi/nfit.c +++ b/drivers/acpi/nfit.c @@ -1131,11 +1131,11 @@ static int acpi_nfit_add_dimm(struct acpi_nfit_desc *acpi_desc, /* * Until standardization materializes we need to consider up to 3 - * different command sets. Note, that checking for zero functions - * tells us if any commands might be reachable through this uuid. + * different command sets. Note, that checking for function0 (bit0) + * tells us if any commands are reachable through this uuid. */ for (i = NVDIMM_FAMILY_INTEL; i <= NVDIMM_FAMILY_HPE2; i++) - if (acpi_check_dsm(adev_dimm->handle, to_nfit_uuid(i), 1, 0)) + if (acpi_check_dsm(adev_dimm->handle, to_nfit_uuid(i), 1, 1)) break; /* limit the supported commands to those that are publicly documented */ @@ -1151,9 +1151,10 @@ static int acpi_nfit_add_dimm(struct acpi_nfit_desc *acpi_desc, if (disable_vendor_specific) dsm_mask &= ~(1 << 8); } else { - dev_err(dev, "unknown dimm command family\n"); + dev_dbg(dev, "unknown dimm command family\n"); nfit_mem->family = -1; - return force_enable_dimms ? 0 : -ENODEV; + /* DSMs are optional, continue loading the driver... */ + return 0; } uuid = to_nfit_uuid(nfit_mem->family); diff --git a/drivers/acpi/utils.c b/drivers/acpi/utils.c index b4de130f2d57..22c09952e177 100644 --- a/drivers/acpi/utils.c +++ b/drivers/acpi/utils.c @@ -680,6 +680,9 @@ bool acpi_check_dsm(acpi_handle handle, const u8 *uuid, u64 rev, u64 funcs) u64 mask = 0; union acpi_object *obj; + if (funcs == 0) + return false; + obj = acpi_evaluate_dsm(handle, uuid, rev, 0, NULL); if (!obj) return false; @@ -692,9 +695,6 @@ bool acpi_check_dsm(acpi_handle handle, const u8 *uuid, u64 rev, u64 funcs) mask |= (((u64)obj->buffer.pointer[i]) << (i * 8)); ACPI_FREE(obj); - if (funcs == 0) - return true; - /* * Bit 0 indicates whether there's support for any functions other than * function 0 for the specified UUID and revision. -- 2.30.2