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| author | Dan Williams | 2016-06-24 18:07:39 +0200 |
|---|---|---|
| committer | Dan Williams | 2016-06-24 18:07:39 +0200 |
| commit | 4995734e973a2c2e9c6f6413cbad9913fc4df0dc (patch) | |
| tree | 1c6fbd2fa0e6d1d064323cddfb8e71e52be6f810 /drivers/acpi/nfit.c | |
| parent | libnvdimm, pfn, dax: fix initialization vs autodetect for mode + alignment (diff) | |
| download | kernel-qcow2-linux-4995734e973a2c2e9c6f6413cbad9913fc4df0dc.tar.gz kernel-qcow2-linux-4995734e973a2c2e9c6f6413cbad9913fc4df0dc.tar.xz kernel-qcow2-linux-4995734e973a2c2e9c6f6413cbad9913fc4df0dc.zip | |
acpi, nfit: fix acpi_check_dsm() vs zero functions implemented
QEMU 2.6 implements nascent support for nvdimm DSMs. Depending on
configuration it may only implement the function0 dsm to indicate that
no other DSMs are available. Commit 31eca76ba2fc "nfit, libnvdimm:
limited/whitelisted dimm command marshaling mechanism" breaks QEMU, but
QEMU is spec compliant. Per the spec the way to indicate that no
functions are supported is:
If Function Index is zero, the return is a buffer containing one bit
for each function index, starting with zero. Bit 0 indicates whether
there is support for any functions other than function 0 for the
specified UUID and Revision ID. If set to zero, no functions are
supported (other than function zero) for the specified UUID and
Revision ID.
Update the nfit driver to determine the family (interface UUID) without
requiring the implementation to define any other functions, i.e.
short-circuit acpi_check_dsm() to succeed per the spec. The nfit driver
appears to be the only user passing funcs==0 to acpi_check_dsm(), so
this behavior change of the common routine should be limited to the
probing done by the nfit driver.
Cc: Len Brown <lenb@kernel.org>
Cc: Jerry Hoemann <jerry.hoemann@hpe.com>
Acked-by: "Rafael J. Wysocki" <rafael@kernel.org>
Fixes: 31eca76ba2fc ("nfit, libnvdimm: limited/whitelisted dimm command marshaling mechanism")
Reported-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Tested-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/acpi/nfit.c')
| -rw-r--r-- | drivers/acpi/nfit.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/acpi/nfit.c b/drivers/acpi/nfit.c index 2215fc847fa9..32579a7b71d5 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 function0 (bit0) - * tells us if any commands are reachable through this uuid. + * different command sets. Note, that checking for zero functions + * tells us if any commands might be 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, 1)) + if (acpi_check_dsm(adev_dimm->handle, to_nfit_uuid(i), 1, 0)) break; /* limit the supported commands to those that are publicly documented */ |