Commit Graph

179 Commits

Author SHA1 Message Date
Gleb Smirnoff
c6499eccad Mechanically substitute flags from historic mbuf allocator with
malloc(9) flags in sys/dev.
2012-12-04 09:32:43 +00:00
Dimitry Andric
29658c96ce Remove duplicate const specifiers in many drivers (I hope I got all of
them, please let me know if not).  Most of these are of the form:

static const struct bzzt_type {
	[...list of members...]
} const bzzt_devs[] = {
	[...list of initializers...]
};

The second const is unnecessary, as arrays cannot be modified anyway,
and if the elements are const, the whole thing is const automatically
(e.g. it is placed in .rodata).

I have verified this does not change the binary output of a full kernel
build (except for build timestamps embedded in the object files).

Reviewed by:	yongari, marius
MFC after:	1 week
2012-11-05 19:16:27 +00:00
Pyun YongHyeon
a8eeb50c81 Remove TCP/UDP checksum offloading feature for IP fragmented
datagrams.  Traditionally upper stack fragmented packets without
computing TCP/UDP checksum and these datagrams were passed to
driver.  But there are chances that other packets slip into the
interface queue in SMP world. If this happens firmware running on
MIPS 4000 processor in the controller would see mixed packets and
it shall send out corrupted packets.
While I'm here simplify checksum offloading setup.

MFC After:	1 week
2012-11-01 05:39:21 +00:00
Alan Cox
3b03ca3bbe Eliminate vestiges of page coloring. 2011-12-15 05:07:16 +00:00
Pyun YongHyeon
b7c2632d6a Overhaul bus_dma(9) usage in driver:
- Don't use a single big DMA block for all rings. Create separate
   DMA area for each ring instead.  Currently the following DMA
   areas are created:
	Event ring, standard RX ring, jumbo RX ring, RX return ring,
	hardware MAC statistics and producer/consumer status area.
   For Tigon II, mini RX ring and TX ring are additionally created.
 - Added missing bus_dmamap_sync(9) in various TX/RX paths.
 - TX ring is no longer created for Tigon 1 such that it saves more
   resources on Tigon 1.
 - Data sheet is not clear about alignment requirement of each ring
   so use 32 bytes alignment for normal DMA area but use 64 bytes
   alignment for jumbo RX ring where the extended RX descriptor
   size is 64 bytes.
 - For each TX/RX buffers use separate DMA tag(e.g. the size of a
   DMA segment, total size of DMA segments etc).
 - Tigon allows separate DMA area for event producer, RX return
   producer and TX consumer which is really cool feature.  This
   means TX and RX path could be independently run in parallel.
   However ti(4) uses a single driver lock so it's meaningless
   to have separate DMA area for these producer/consumer such that
   this change creates a single status DMA area.
 - It seems Tigon has no limits on DMA address space and I also
   don't see any problem with that but old comments in driver
   indicates there could be issues on descriptors being located in
   64bit region.  Introduce a tunable, dev.ti.%d.dac, to disable
   using 64bit DMA in driver. The default is 0 which means it would
   use full 64bit DMA.  If there are DMA issues, users can disable
   it by setting the tunable to 0.
 - Do not increase watchdog timer in ti_txeof(). Previously driver
   increased the watchdog timer whenever there are queued TX frames.
 - When stat ticks is set to 0, skip processing ti_stats_update(),
   avoiding bus_dmamap_sync(9) and updating if_collisions counter.
 - MTU does not include FCS bytes, replace it with
   ETHER_VLAN_ENCAP_LEN.

With these changes, ti(4) should work on PAE environments.
Many thanks to Jay Borkenhagen for remote hardware access.
2011-11-14 20:38:14 +00:00
Pyun YongHyeon
e79b243289 Export sysctl node for various interrupt moderation parameters and
have administrators control them.  ti(4) provides a character
device to control various other features of driver via ioctls but
users had to write their own code to manipulate these parameters.
It seems some default values for these parameters are not optimal
on today's system but leave it as it was and let administrators
change them.  The following parameters could be changed:

dev.ti.%d.rx_coal_ticks
dev.ti.%d.rx_max_coal_bds
dev.ti.%d.tx_coal_ticks
dev.ti.%d.tx_max_coal_bds
dev.ti.%d.tx_buf_ratio
dev.ti.%d.stat_ticks

The interface has to be brought down and up again before a change
takes effect.

ti(4) controller supports hardware MAC counters with additional
DMA statistics.  So it's doable to export these counters via
sysctl interface.  Unfortunately, these counters are cumulative
such that driver have to either send an explicit clear command to
controller after extracting them or have to maintain internal
counters to get actual changes.  Neither look good to me so
counters were not exported via sysctl.
2011-11-14 19:10:20 +00:00
Pyun YongHyeon
9b81d5e37f It's bad idea to allocate large memory, 4KB, from stack.
Pre-allocate the memory in device attach time. While I'm here
remove unnecessary reassignment of error variable as it was already
initialized. Also added a missing driver lock in TIIOCSETTRACE
handler.
2011-11-14 18:40:04 +00:00
Pyun YongHyeon
ecf3f60fed Remove dead ifdef. Driver should always check raised interrupt is
for the device.
2011-11-10 23:14:04 +00:00
Pyun YongHyeon
8a9710aa8c style.
No functional changes.
2011-11-10 22:15:11 +00:00
Pyun YongHyeon
10a4360c80 Retire 'options TI_PRIVATE_JUMBOS' and replace local jumbo
allocator with UMA backed jumbo allocator by default. Previously
ti(4) used sf_buf(9) interface for jumbo buffers but it was broken
at this moment such that enabling jumbo frame caused instant panic.
Due to the nature of sf_buf(9) it heavily relies on VM changes but
it seems ti(4) was not received much blessing from VM gurus.  I
don't understand VM magic and implications used in driver either.
Switching to UMA backed jumbo allocator like other network drivers
will make jumbo frame work on ti(4).
While I'm here, fully allocate all RX buffers. This means ti(4) now
uses 512 RX buffer and 1024 mini RX buffers.

To use sf_buf(9) interface for jumbo buffers, introduce a new
'options TI_SF_BUF_JUMBO'. If it is proven that sf_buf(9) is better
for jumbo buffers, interesting developers can fix the issue in
future.

ti(4) still needs more bus_dma(9) cleanups and should use separate
DMA tag/map for each ring(standard, jumbo, mini, command, event
etc) but it should work on all platforms except PAE.

Special thanks to Jay[1] who provided complete remote debugging
access.

Tested by:	Jay Borkenhagen <jayb <> braeburn dot org > [1]
2011-11-08 18:23:02 +00:00
Pyun YongHyeon
f9ea040e0c Do not allow changing MTU to be less than the minimum. 2011-11-07 22:58:49 +00:00
Pyun YongHyeon
aeeee7eec1 If ti_chipinit() fails in ti_stop(), ignore the error and release
all allocated TX/RX buffer resources. If the interface is brought
to up again after the error, we will leak allocated TX/RX buffers.
2011-11-07 22:53:06 +00:00
Pyun YongHyeon
4fce1b52ed Show RX buffer allocation failure and do not blindly send alive
message to firmware. Probably the correct way for this error is to
send a TI_CMD_CODE_STACK_DOWN message to firmware and let firmware
handle the rest.
2011-11-07 22:47:25 +00:00
Pyun YongHyeon
6280f2fb34 Mini ring is not available on Tigon 1 so do not create DMA maps for
mini ring on Tigon 1 to save resources.
2011-11-07 22:17:44 +00:00
Pyun YongHyeon
7beaf112a5 Track which ring was updated in RX handler and update only modified
ring. This should reduce unnecessary register accesses.
2011-11-07 22:11:38 +00:00
Pyun YongHyeon
18707510b7 o Remove unnecessary controller reinitialization.
o Do not blindly UP controller when MTU is changed. Reinitialize
   controller only if driver is running.
 o Remove useless ti_stop() in ti_watchdog() since ti_init_locked()
   always invokes ti_stop().
2011-11-07 18:26:38 +00:00
Pyun YongHyeon
bb6ebb6af8 Remove ti_unit member variable in softc.
While I'm here use PCIR_BAR macro.
2011-11-07 18:19:20 +00:00
Pyun YongHyeon
129f7efda9 Implement altq(4) support.
While I'm here fix a logic error in r227098 where it didn't
re-enable interrupts when TX queue is empty.
2011-11-04 23:34:54 +00:00
Pyun YongHyeon
9c6960c61c Because ti(4) drops a driver lock in RX handler, check whether
driver is still running before re-enabling interrupts.
2011-11-04 23:09:57 +00:00
Pyun YongHyeon
85d21e66be Don't abuse if_hwassist and make sure enabling corresponding TX/RX
checksum offloading and VLAN hardware tag insertion/stripping from
the currently enabled hardware offloading capabilities.
Previously if_hwassist, which was initialized to TX/RX checksum
offloading, was blindly used to enable both TX and RX checksum
offloading such that disabling either TX or RX checksum offloading
was not possible.

ti(4) controllers support TX/RX checksum offloading with VLAN
tagging so announce TX/RX checksum offloading capability over VLAN
to vlan(4).

Make VLAN hardware tag insertion/stripping honors currently enabled
interface capability instead of blindly enabling VLAN hardware
tagging. This change allows disabling hardware support of VLAN tag.

Because ti(4) supports VLAN oversized frames, make network stack
know the capability by setting if_hdrlen.

While I'm here, rewrite SIOCSIFCAP handler and make sure to
reinitialize controller whenever TX/RX checksum offloading and VLAN
hardware tagging option is changed.  The requirement of controller
reinitialization comes from the limitation of Tigon I/II firmware.
Tigon I/II firmware requires all related RCBs should be
reinitialized whenever any of its hardware offloading capabilities
change.

vlan(4) is also notified whenever the parent interface's capability
changes such that it can correctly handle TX/RX checksum offloading
based on parent interface's enabled offloading capabilities.

RX checksum offloading handler was changed to make upper stack use
controller computed partial checksum value.  Previously, ti(4) just
set the computed value for any frames(IPv4, IPv6) and the value was
not used in upper stack because driver didn't set CSUM_DATA_VALID
such that upper network stack had to recompute checksum of TCP/UDP
packets. I have no idea how this was not noticed for a long time.
With this change, upper network stack does not have to fully
recompute the checksum such that calculating pseudo checksum based
on partial checksum is sufficient to know whether received packet's
checksum is correct or not. However, I don't know why ti(4) does
not have controller compute pseudo checksum as controller has
ability to do it. I'm just guessing enabling that feature could
trigger a firmware bug or could be slower than computing it on host
side so just leave it as it was.

In order not to produce false positives, ti(4) now checks whether
controller actually computed IP or TCP/UDP checksum by checking
ti_flags field.
2011-11-04 22:53:52 +00:00
Pyun YongHyeon
9645f9eb0b Don't clear upper 4bits from VLAN tag information. It's
responsibility of vlan(4) to extract VLAN id from the tag
information and vlan(4) correctly handles it.
2011-11-04 21:42:13 +00:00
Pyun YongHyeon
148386d9aa Introduce ti_ifmedia_upd_locked() to use in driver initialization
and add missing driver lock for both ti_ifmedia_upd() and
ti_ifmedia_sts().
2011-11-04 21:30:46 +00:00
Pyun YongHyeon
945c212659 Announce IFCAP_LINKSTATE capability and let network stack know link
state changes.  Hide superfluous link up/down message under
bootverbose since if_link_state_change(9) shows that information.
While I'm here, change baudrate with the resolved speed of the
established link instead of blindly setting it 1G. Unfortunately,
it seems there is no way to differentiate 10/100Mbps from
non-gigabit link so just assume we established a 100Mbps link if
current link is not a gigabit link.
2011-11-04 20:43:37 +00:00
Pyun YongHyeon
5948254c2a Make sure to unload loaded DMA area(descriptor, command, event ring). 2011-11-04 20:25:30 +00:00
Pyun YongHyeon
5ddfea8c43 s/u_intXX_t/uintXX_t/g 2011-11-04 19:12:07 +00:00
Pyun YongHyeon
ee715c5ff4 Make ti(4) build with 'options TI_PRIVATE_JUMBOS'.
This was broken in r175872.

We have a UMA backed jumbo allocator and that is much better
implementation than having a local jumbo buffer allocator in
driver. This local allocator would be removed in near future but
fixing build before removal wouldn't be a bad idea.
2011-11-04 18:39:39 +00:00
Pyun YongHyeon
504dc87bf4 style.
No functional changes.
2011-11-04 18:28:10 +00:00
Pyun YongHyeon
7034f3ad36 Use ANSI function definations. 2011-11-04 17:07:53 +00:00
Marius Strobl
a1d090d428 - Allocate the DMA memory shared between the host and the controller as
coherent.
- Constify the ti_devs table.
- Don't bother to set if_mtu to ETHERMTU, ether_ifattach() does that.

MFC after:	2 weeks
2011-03-11 22:32:17 +00:00
Alan Cox
492d01762f Neither the page lock nor the page queues lock is required to unwire and
free a VM_ALLOC_NOOBJ page.  (Such pages are unmanaged.)
2010-05-03 15:51:59 +00:00
John Baldwin
7cf545d0a1 - Add a private timer to drive the transmit watchdog instead of using
if_watchdog and if_timer.
- Fix some issues in detach for sn(4), ste(4), and ti(4).  Primarily this
  means calling ether_ifdetach() before anything else.
2009-11-19 22:06:40 +00:00
Robert Watson
eb956cd041 Use if_maddr_rlock()/if_maddr_runlock() rather than IF_ADDR_LOCK()/
IF_ADDR_UNLOCK() across network device drivers when accessing the
per-interface multicast address list, if_multiaddrs.  This will
allow us to change the locking strategy without affecting our driver
programming interface or binary interface.

For two wireless drivers, remove unnecessary locking, since they
don't actually access the multicast address list.

Approved by:	re (kib)
MFC after:	6 weeks
2009-06-26 11:45:06 +00:00
Marius Strobl
44f8f2fc05 Remove some remnant alpha hacks.
Approved by:	PCI-maintainers (imp, jhb)
2008-04-26 14:13:48 +00:00
Christian Brueffer
662cac9f23 Fix some "in in" typos in comments.
PR:		121490
Submitted by:	Anatoly Borodin <anatoly.borodin@gmail.com>
Approved by:	rwatson (mentor), jkoshy
MFC after:	3 days
2008-03-26 07:32:08 +00:00
Remko Lodder
f17edc7494 Set the baudrate for if_ti.
PR:		kern/40516
Submitted by:	"Jin Guojun[VFF]" <jin at adsl-63-198-35-122 dot dsl dot snfc21 dot pacbell dot net>
Approved by:	imp (mentor, implicit for minor changes)
MFC After:	1 week
2008-02-19 20:54:42 +00:00
Poul-Henning Kamp
cf827063a9 Give MEXTADD() another argument to make both void pointers to the
free function controlable, instead of passing the KVA of the buffer
storage as the first argument.

Fix all conventional users of the API to pass the KVA of the buffer
as the first argument, to make this a no-op commit.

Likely break the only non-convetional user of the API, after informing
the relevant committer.

Update the mbuf(9) manual page, which was already out of sync on
this point.

Bump __FreeBSD_version to 800016 as there is no way to tell how
many arguments a CPP macro needs any other way.

This paves the way for giving sendfile(9) a way to wait for the
passed storage to have been accessed before returning.

This does not affect the memory layout or size of mbufs.

Parental oversight by:	sam and rwatson.

No MFC is anticipated.
2008-02-01 19:36:27 +00:00
Pyun YongHyeon
6a087a8722 Fix function prototype for device_shutdown method. 2007-11-22 02:45:00 +00:00
Christian S.J. Peron
59a0d28bac Catch up the rest of the drivers with the ether_vlan_mtap modifications.
If these drivers are setting M_VLANTAG because they are stripping the
layer 2 802.1Q headers, then they need to be re-inserting them so any
bpf(4) peers can properly decode them.

It should be noted that this is compiled tested only.

MFC after:	3 weeks
2007-03-04 03:38:08 +00:00
Paolo Pisati
ef544f6312 o break newbus api: add a new argument of type driver_filter_t to
bus_setup_intr()

o add an int return code to all fast handlers

o retire INTR_FAST/IH_FAST

For more info: http://docs.freebsd.org/cgi/getmsg.cgi?fetch=465712+0+current/freebsd-current

Reviewed by: many
Approved by: re@
2007-02-23 12:19:07 +00:00
Marius Strobl
c2175ff5ca Change the remainder of the drivers for DMA'ing devices enabled in the
sparc64 GENERIC and the sound device drivers known working on sparc64
to use bus_get_dma_tag() to obtain the parent DMA tag so we can get rid
of the sparc64_root_dma_tag kludge eventually. Except for ath(4), sk(4),
stge(4) and ti(4) these changes are runtime tested (unless I booted up
the wrong kernels again...).
2007-01-21 19:32:51 +00:00
Andre Oppermann
78ba57b9e1 Move ethernet VLAN tags from mtags to its own mbuf packet header field
m_pkthdr.ether_vlan.  The presence of the M_VLANTAG flag on the mbuf
signifies the presence and validity of its content.

Drivers that support hardware VLAN tag stripping fill in the received
VLAN tag (containing both vlan and priority information) into the
ether_vtag mbuf packet header field:

	m->m_pkthdr.ether_vtag = vlan_id;	/* ntohs()? */
	m->m_flags |= M_VLANTAG;

to mark the packet m with the specified VLAN tag.

On output the driver should check the mbuf for the M_VLANTAG flag to
see if a VLAN tag is present and valid:

	if (m->m_flags & M_VLANTAG) {
		... = m->m_pkthdr.ether_vtag;	/* htons()? */
		... pass tag to hardware ...
	}

VLAN tags are stored in host byte order.  Byte swapping may be necessary.

(Note: This driver conversion was mechanic and did not add or remove any
byte swapping in the drivers.)

Remove zone_mtag_vlan UMA zone and MTAG_VLAN definition.  No more tag
memory allocation have to be done.

Reviewed by:	thompsa, yar
Sponsored by:	TCP/IP Optimization Fundraise 2005
2006-09-17 13:33:30 +00:00
Gleb Smirnoff
6b9f5c941c - Consistently use if_printf() only in interface methods: if_start(),
if_watchdog, etc., or in functions used only in these methods.
  In all other functions in the driver use device_printf().
- Use __func__ instead of typing function name.

Submitted by:	Alex Lyashkov <umka sevcity.net>
2006-09-15 15:16:12 +00:00
Pyun YongHyeon
329532e54e Fix invalid reference of mbuf chains.
Use proper pointer dereference to inform modified mbuf chains to
caller.

While I'm here perform checksum offload setup after loading DMA
maps.

In collaboration with:  glebius
2006-08-12 01:30:38 +00:00
Pyun YongHyeon
ff3ced1270 - Tx side bus_dmamap_load_mbuf_sg(9) support. This reduces bookkeeping
requiried to keep consistent softc state before/after callback function
  invocation and supposed to be sligntly faster than previous one as it
  wouldn't incur callback overhead. With this change callback function
  was gone.
- Decrease TI_MAXTXSEGS to 32 from 128. It seems that most mbuf chain
  length is less than 32 and it would be re-packed with m_defrag(9) if
  its chain length is larger than TI_MAXTXSEGS. This would protect ti(4)
  against possible kernel stack overflow when txsegs[] is put on stack.
  Alternatively, we can embed the txsegs[] into softc. However, that
  would waste memory and make Tx/Rx speration hard when we want to
  sperate Tx/Rx handlers to optimize locking.
- Fix dma map tracking used in Tx path. Previously it used the dma map
  of the last mbuf chain in ti_txeof() which was incorrect as ti(4)
  used dma map of the first mbuf chain when it loads a mbuf chain with
  bus_dmamap_load_mbuf(9). Correct the bug by introducing queues that
  keep track of active/inactive dma maps/mbuf chain.
- Use ti_txcnt to check whether driver need to set watchdog timer instead
  of blidnly clearing the timer in ti_txeof().
- Remove the 3rd arg. of ti_encap(). Since ti(4) now caches the last
  descriptor index(ti_tx_saved_prodidx) used in Tx there is no need to
  pass it as a fuction arg.
- Change data type of producer/consumer index to int from u_int16_t in
  order to remove implicit type conversions in Tx/Rx handlers.
- Check interface queue before getting a mbuf chain to reduce locking
  overhead.
- Check number of available Tx descriptores to be 16 or higher in
  ti_start(). This wouldn't protect Tx descriptor shortage but it would
  reduce number of bus_dmamap_unload(9) calls in ti_encap() when we are
  about to running out of Tx descriptors.
- Command NIC to send packets ony when the driver really has packets
  enqueued. Previously it always set TI_MB_SENDPROD_IDX which would
  command NIC to DMA Tx descriptors into NIC local memory regardless
  of Tx descriptor changes.

Reviewed by:	scottl
2006-01-03 06:14:07 +00:00
Scott Long
557e53c6f7 Cache the tx producer index instead of reading it every time ti_start is
called.
2005-12-28 08:36:32 +00:00
Scott Long
3c41ebd1f8 Fix a serious regression from the busdma conversion. Check to make sure
that we don't overrun the tx descriptor ring before actually trying to
overrun it.
2005-12-28 08:14:35 +00:00
Pyun YongHyeon
d54c905707 Bring big-endian architecture support for ti(4).
. remove unnecessay header files after Scott's bus_dma(9) commit.
 . remove global variable tis which was introduced at the time of
   zero_copy(9) changes. The variable tis was not used at all. The
   same applyes to ti_links in softc so axe it.
 . deregister variables.
 . axe ti_vhandle and switch to use explicit register access for
   accessing NIC local memory. Creates three variants of ti_mem to
   read/write NIC local memory(ti_mem_read, ti_mem_write) and clearing
   NIC local memory(ti_mem_zero). This greatly enhances code
   readability and have ti(4) drop using shared memory scheme for
   Tigon 1. As Tigon 1 switched to use explicit register access for Tx,
   axe ti_tx_ring_nic/ti_cmd_ring in softc.(Tigon 2 used to host ring
   scheme which means there is no need to access NIC local memory via
   register access for Tx and NIC would DMA the modified Tx rings into
   its local memory.) [1]
 . introduce new macro TI_EVENT_*/TI_CMD_* to handle NIC envent/command.
   Instead of using bit fields assginment for accessing the event, use
   shift operations to set/get it. [1]
 . add additional check for valid DMA tags in ti_free_dmamaps().
 . add missing bus_dmamap_sync/bus_dmamap_unload in ti_free_*_ring_*.
 . fix locking nits(MTX_RECURSE mutex) and make ti(4) MPSAFE.
 . change data type of ti_rdata_phys to bus_addr_t and don't blindly
   cast to uint32_t.
 . rearrange detach path and make ti(4) survive during device detach.
 . for Tigon 1, use explicit register access for checking Tx descriptors
   in ti_encap()/ti_txeof(). [1]
 . properly call bus_dmamap_sync(9) for updating statistics.
 . remove extra semicolon in ti_encap()
 . rewrite loading MAC address to work on strict-alignment architectures.
 . move TI_RD_OFF macro to if_tireg.h
 . axe ETHER_ALIGN as it's already defined in <net/ethernet.h>.
 . make macros immuine from expansion by adding parenthesis and do-while.
 . remove alpha specific hack as vtophys(9) is no longer used in ti(4)
   after Scott's bus_dma(9) fix.

Reviewed by:	scottl
Obtained from:	OpenBSD [1]
2005-12-28 02:57:19 +00:00
Gleb Smirnoff
d147662cd3 - Fix VLAN_INPUT_TAG() macro, so that it doesn't touch mtag in
case if memory allocation failed.
- Remove fourth argument from VLAN_INPUT_TAG(), that was used
  incorrectly in almost all drivers. Indicate failure with
  mbuf value of NULL.

In collaboration with:	yongari, ru, sam
2005-12-18 18:24:27 +00:00
Scott Long
6239708b1c Fix the Tigon I/II driver to support 64-bit DMA. In the process, convert it
to use busdma.  Unlike most of the other drivers, but similar to the
if_em driver, pre-allocate the dmamaps at init time instead of allocating
them on the fly when descriptors need to be filled.  This isn't ideal right
now because a map is allocated for every descriptor slot in the tx, rx, mini,
and jumbo rings (which is a lot!) in order to simplify the bookkeeping, even
though the driver might support filling only a subset of those slots.
Luckily, maps are typically NULL on i386 and amd64, so the cost isn't
very high.  It could be an issue with sparc64, but the driver isn't endian
clean either, and that is a much bigger problem to solve first.

Note that jumbo frame support is under-tested, and I'm not even sure if
it till really works correctly given the evil VM magic that is does.
The changes here attempt to preserve the existing semanitcs.

Thanks to Martin Nillson for contributing the Netgear card for this work.

MFC-After: 3 weeks
2005-12-14 00:03:41 +00:00
Scott Long
d29dab303f Allocate the jumbo rx frame buffer with busdma. 2005-12-10 08:58:48 +00:00