Until we can have perfect knowledge that all callers above us think it's okay
for us to sleep, releasing *our* locks of course, we don't dare try and sleep.
in connection with Marvell based SATA->PATA dongles.
The problem was caused by a combination of things working
together to make it hard to spot...
The ATA driver has always started the ATA command, then build
the SG list for DMA and then finally started the DMA engine.
While this is according to specs, it poses a potential
problem as some controllers apparently do not allow for unlimitted
time between starting the ATA command and starting the DMA engine.
At about the same time as ATAng was committed there were lots
of other changes applied, some of which was locking in parts
that causes the busdma load functions to take significantly
longer to load the SG list.
This pushed the time spent between starting the ATA command and
starting the DMA engine over the hill for some controllers
(especially the Silicon Image DS3112a) and caused what looked
like lost interrupts.
The solution is to get all the SG list work or rather all
busdma related stuff done before we even try to start anything.
This has the nice side effect of seperating busdma out the
way it should be, so the working of the ATA machinery is not
cluttered up with busdma droppings, making the code easier
to read and understand.
sysctl that a given variable is tunable.
Also added is CTLFLAG_RDTUN, which is CTLFLAG_RD|CTLFLAG_TUN; TUN does
not always imply read-only, so RDTUN should be used where RD was used
before.
for dev_strategy() use.
Retire bio_driver[12] (aliases for b_io.bio_driver[12]) these fields are
reserved for device driver use and can as such never have any interest
in the buf end of things.
rate is how fast modems exchange symbols. Bit rate is how many bits
per second the serial port nominally communicates at. Try to use bit
rate consistently where that's what is ment. The default data rate is
now 9600 baud. 300 baud being default pre-dates 4.4-LITE1. Document
that tip doesn't respect the system default rate for a given channel.
Sorry guys, but no ucbvax, kremvax or kgbvax added to the example.
Noted by: bde
closer to reality. More work remains to be done. st_mtime should
be the most complete based on IEEE Std 1003.1, 2003 Edition, a
review of ufs_vnops.c, and some experimentation.
- Return NULL instead of returning memory outside of the stackgap
in stackgap_alloc() (FreeBSD-SA-00:42.linux)
- Check for stackgap_alloc() returning NULL in svr4_emul_find(),
and clean_pipe().
- Avoid integer overflow on large nfds argument in svr4_sys_poll()
- Reject negative nbytes argument in svr4_sys_getdents()
- Don't copy out past the end of the struct componentname
pathname buffer in svr4_sys_resolvepath()
- Reject out-of-range signal numbers in svr4_sys_sigaction(),
svr4_sys_signal(), and svr4_sys_kill().
- Don't malloc() user-specified lengths in show_ioc() and
show_strbuf(), place arbitrary limits instead.
- Range-check lengths in si_listen(), ti_getinfo(), ti_bind(),
svr4_do_putmsg(), svr4_do_getmsg(), svr4_stream_ti_ioctl().
Some fixes obtain from OpenBSD.
