present and thus that the PnPBIOS probe should be skipped instead of
having ACPI zero out the PnPBIOStable pointer.
- Make the PnPBIOStable pointer static to i386/i386/bios.c now that that is
the only place it is used.
its primary use is for the FEPS/FAS366 SCSI found in Sun Ultra 1e and 2
machines. Once the pci front-end is ported, this driver can replace the
amd(4) driver.
The code as-is is fairly stable. I've disabled tagged-queueing until I can
figure out a corruption bug related to it. I'm importing it now so that
people with these machines can (finally) stop netbooting and report bugs
before 5.3.
as otherwise the junk it contains may cause uhub_explore to give
up without ever trying to restart the port. This fixes the following
errors I was seeing with a VIA UHCI controller:
uhub0: port error, restarting port 1
uhub0: port error, giving up port 1
(time grows downward)
thread 1 thread 2
------------|------------
dec ref_cnt |
| dec ref_cnt <-- ref_cnt now zero
cmpset |
free all |
return |
|
alloc again,|
reuse prev |
ref_cnt |
| cmpset, read
| already freed
| ref_cnt
------------|------------
This should fix that by performing only a single
atomic test-and-set that will serve to decrement
the ref_cnt, only if it hasn't changed since the
earlier read, otherwise it'll loop and re-read.
This forces ordering of decrements so that truly
the thread which did the LAST decrement is the
one that frees.
This is how atomic-instruction-based refcnting
should probably be handled.
Submitted by: Julian Elischer
on all inputs of the form x.75, where x is an even integer and
log2(x) = 21. A similar problem occurred when rounding upward.
The bug involves the following snippet copied from rint():
i>>=1;
if((i0&i)!=0) i0 = (i0&(~i))|((0x100000)>>j0);
The constant 0x100000 should be 0x200000. Apparently this case was
never tested.
It turns out that the bit manipulation is completely superfluous
anyway, so remove it. (It tries to simulate 90% of the rounding
process that the FPU does anyway.) Also, the special case of +-0 is
handled twice (in different ways), so remove the second instance.
Throw in some related simplifications from bde:
- Work around a bug where gcc fails to clip to float precision by
declaring two float variables as volatile. Previously, we
tricked gcc into generating correct code by declaring some
float constants as doubles.
- Remove additional superfluous bit manipulation.
- Minor reorganization.
- Include <sys/types.h> explicitly.
Note that some of the equivalent lines in rint() also appear to be
unnecessary, but I'll defer to the numerical analysts who wrote it,
since I can't test all 2^64 cases.
Discussed with: bde
internal reference counters, UMA_ZONE_NOFREE. This way, those slabs
(with their ref counts) will be effectively type-stable, then using
a trick like this on the refcount is no longer dangerous:
MEXT_REM_REF(m);
if (atomic_cmpset_int(m->m_ext.ref_cnt, 0, 1)) {
if (m->m_ext.ext_type == EXT_PACKET) {
uma_zfree(zone_pack, m);
return;
} else if (m->m_ext.ext_type == EXT_CLUSTER) {
uma_zfree(zone_clust, m->m_ext.ext_buf);
m->m_ext.ext_buf = NULL;
} else {
(*(m->m_ext.ext_free))(m->m_ext.ext_buf,
m->m_ext.ext_args);
if (m->m_ext.ext_type != EXT_EXTREF)
free(m->m_ext.ref_cnt, M_MBUF);
}
}
uma_zfree(zone_mbuf, m);
Previously, a second thread hitting the above cmpset might
actually read the refcnt AFTER it has already been freed. A very
rare occurance. Now we'll know that it won't be freed, though.
Spotted by: julian, pjd
all of the interface between the driver and the bus. This will enable
us to stop special casing eisa bus attachments in modules and treat them
like we treat all other busses.
In the longer run, we need to eliminate much (all?) of these interfaces
and switch to using the standard bus_alloc_resource(), but that's not
done right now.
# I've not updated the modules to include eisa, etc, just yet
Tested on: Compaq Proliant 3000/333 purchased for eisa work
mode. The 5704 apparently has some s00p3r s33kr1t registers for setting
the advertisement of pause frame ability (i.e flow control) when in
autoneg mode. If we don't set these registers correctly, we may not
be able to negotiate a proper link with some switches. (Symptom is that
the NIC reports the link as up (PCS synched) but no traffic can be
exchanged.)
PR: kern/67598
Add two new functions: ttyref() and ttyrel(). ttymalloc() creates a struct
tty with a reference count of one. when ttyrel sees the count go to zero,
struct tty is freed.
Hold references for open ttys and for ttys which are controlling terminal
for sessions.
Until drivers start using ttyrel(), this commit will make no difference.
