constrained to a small number of sessions by the small on-card memories found
in newer devices. This is really a stopgap solution as having session state
in main memory incurs a (small but noticeable) performance penalty. The better
solution is to manage session state so that it's cached on chip.
Obtained from: openbsd
* Get flags first, in case there is no devclass.
* Reset flags after each probe in case the next driver has no hints so it
doesn't inherit the old ones.
* Set them again before the winning probe.
Tested ok both with and without ACPI for ISA device flags.
Reviewed by: imp
MFC after: 1 day
providers for tasting. Before this hack, race below is possible:
SI_SUB_RAID (no not-fully-configured geoms, so don't block)
GEOM tasting (now geoms are created)
SI_SUB_MOUNT_ROOT (if root file system is placed on a mirror, it is
possible that this mirror is not fully configured yet)
There is a lot of work to do to avoid such hacks and I need a working
solution before 5.3, sorry.
Reported by: John Hay <jhay@icomtek.csir.co.za>
We have to use our own destroy_geom method, because default one, which
is a part of geom_slice is broken.
MT5 candidate.
PR: kern/72467
Submitted by: Vladimir Novoseltsev
The changes in the next commit would make the code totally unreadable
if the #ifdef'ing were maintained.
It might make a lot of sense to split if_cx.c in a netgraph related
and in a tty related file but I will not attempt that without hardware.
handle DMA addresses located above 1GB. The LBA(loop begin address)
register which holds DMA base address is 32bits register. But the
MSB 2bits are used for other purposes. This effectivly limits the
DMA address space up to 1GB.
Approved by: jake (mentor)
Reviewed by: truckman, matk
assign DMA address to the wrong address. It can cause system lockup
or other mysterious errors. Since most sound cards requires low DMA
address(BUS_SPACE_MAXADDR_24BIT) sndbuf_alloc() would fail when the
audio driver is loaded after long running of operations.
Approved by: jake (mentor)
Reviewed by: truckman, matk
- Implement dcons_ischar() and dcons_load_buffer().
- If loader passed a dcons buffer address, keep using it.
(We still need a patch to cheat memory management system.)
asynchronous. I realize that this means the custom application will
not work as written, but it is not okay to break most users of ugen(4).
The major problem is that a bulk read transfer is not an interrupt
saying that X bytes are available -- it is a request to be able to
receive up to X bytes, with T timeout, and S short-transfer-okayness.
The timeout is a software mechanism that ugen(4) provides and cannot
be implemented using asynchronous reads -- the timeout must start at
the time a read is done.
The status of up to how many bytes can be received in this transfer
and whether a short transfer returns data or error is also encoded
at least in ohci(4)'s requests to the controller. Trying to detect
the "maximum width" results in using a single buffer of far too
small when an application requests a large read.
Even if you combat this by replacing all buffers again with the
maximal sized read buffer (1kb) that ugen(4) would allow you to
use before, you don't get the right semantics -- you have to
throw data away or make all the timeouts invalid or make the
short-transfer settings invalid.
There is no way to do this right without extending the ugen(4) API
much further -- it breaks the USB camera interfaces used because
they need a chain of many maximal-width transfers, for example, and
it makes cross-platform support for all the BSDs gratuitously hard.
Instead of trying to do select(2) on a bulk read pipe -- which has
neither the information on desired transfer length nor ability to
implement timeout -- an application can simply use a kernel thread
and pipe to turn that endpoint into something poll-able.
It is unfortunate that bulk endpoints cannot provide the same semantics
that interrupt and isochronous endpoints can, but it is possible to just
use ioctl(USB_GET_ENDPOINT_DESC) to find out when different semantics
must be used without preventing the normal users of the ugen(4) device
from working.
The original idea was to use it for firmware upgrading and similar
operations. In real life almost all Bluetooth USB devices do not
need firmware download. If device does require firmware download
then ugen(4) (or specialized driver like ubtbcmfw(8)) should be
used instead.
MFC after: 3 days
