Document the diagnostic message printed at startup time. Keep the

list of diagnostic messages sorted.

Document the recently introduced EOPNOTSUPP error return.  Repair
sort ordering for the list of error descriptions.

MFC after:	3 days

1 files changed, 26 insertions, 7 deletions

diff --git a/share/man/man4/hwpmc.4 b/share/man/man4/hwpmc.4
index 4b6237f..9dd5d1c 100644
--- a/share/man/man4/hwpmc.4
+++ b/share/man/man4/hwpmc.4
@@ -487,13 +487,20 @@ that intend to write values larger than 2^31 into these PMCs with
 need to be aware of this hardware limitation.
 .Sh DIAGNOSTICS
 .Bl -diag
+.It "hwpmc: [class/npmc/capabilities]..."
+Announce the presence of
+.Va npmc
+PMCs of class
+.Va class ,
+with capabilities described by bit string
+.Va capabilities .
+.It "hwpmc: kernel version (0x%x) does not match module version (0x%x)."
+The module loading process failed because a version mismatch was detected
+between the currently executing kernel and the module being loaded.
 .It "hwpmc: this kernel has not been compiled with 'options HWPMC_HOOKS'."
 The module loading process failed because the currently executing kernel
 was not configured with the required configuration option
 .Cd HWPMC_HOOKS .
-.It "hwpmc: kernel version (0x%x) does not match module version (0x%x)."
-The module loading process failed because a version mismatch was detected
-between the currently executing kernel and the module being loaded.
 .It "hwpmc: tunable hashsize=%d must be greater than zero."
 A negative value was supplied for tunable
 .Va kern.hwpmc.hashsize .
@@ -545,6 +552,10 @@ PMC using the same hardware resources attached to it.
 A
 .Dv PMC_OP_PMCRW
 request writing a new value was issued on a PMC that was active.
+.It Bq Er EBUSY
+A
+.Dv PMC_OP_PMCSETCOUNT
+request was issued on a PMC that was active.
 .It Bq Er EDOOFUS
 A
 .Dv PMC_OP_PMCSTART
@@ -554,10 +565,6 @@ PMC allocated with
 and
 .Dv PMC_F_LOG_PROCEXIT
 modifiers.
-.It Bq Er EBUSY
-A
-.Dv PMC_OP_PMCSETCOUNT
-request was issued on a PMC that was active.
 .It Bq Er EEXIST
 A
 .Dv PMC_OP_PMCATTACH
@@ -667,6 +674,11 @@ or
 .Dv PMC_OP_PMCSTOP
 request was issued for a system-wide PMC that was allocated on a
 currently disabled CPU.
+.It Bq Er EOPNOTSUPP
+A
+.Dv PMC_OP_PMCALLOCATE
+request was issued for PMC capabilities not supported
+by the specified PMC class.
 .It Bq Er EPERM
 A
 .Dv PMC_OP_PMCADMIN
@@ -721,3 +733,10 @@ at the time of initialization (i.e., at module load time).
 On CPUs supporting logical processors, the driver could misbehave if
 logical processors are subsequently enabled or disabled while the
 driver is active.
+.Pp
+On x86 architectures, the driver requires that the local APIC on the
+CPU be enabled for sampling mode to be supported.
+Many single-processor motherboards keep the APIC disabled in BIOS; on
+such systems
+.Nm
+will not support sampling PMCs.