kernel_optimize_test/drivers/firewire
Stefan Richter 090699c053 firewire: ohci: always use packet-per-buffer mode for isochronous reception
This is a minimal change meant for the short term:  Never set the
ohci->use_dualbuffer flag to true.

There are two reasons to do so:

  - Packet-per-buffer mode and dual-buffer mode do not behave the same
    under certain circumstances, notably if several packets are covered
    by a single fw_cdev_iso_packet descriptor.
    http://marc.info/?l=linux1394-devel&m=124965653718313
    Therefore the driver stack should not silently choose one or the
    other mode but should leave the choice to the high-level driver
    (regardless if kernel driver or userspace driver).  Or simply always
    only offer packet-per-buffer mode, since a considerable number of
    controllers, even current ones, does not offer dual-buffer support.

  - Even under circumstances where packet-per-buffer mode and
    dual-buffer mode behave exactly the same --- notably when used
    through libraw1394, libdc1394, as well as the current two kernel
    drivers which use isochronous reception (firewire-net and firedtv)
    --- we are still faced with the problem that several OHCI 1.1
    controllers have bugs in dual-buffer mode.  Although it looks like
    we have identified most of those buggy controllers by now, we
    cannot be quite sure about that.

So, use packet-per-buffer by default from now on.  This change should
be followed up by a more complete solution:  Either extend the
in-kernel API and the userspace ABI by a choice between the two IR modes
or remove all dual-buffer related code from firewire-ohci.

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
2009-12-29 19:58:17 +01:00
..
core-card.c firewire: core: optimize Topology Map creation 2009-10-14 23:10:48 +02:00
core-cdev.c firewire: cdev: fix another memory leak in an error path 2009-12-29 19:58:16 +01:00
core-device.c
core-iso.c
core-topology.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2009-12-09 19:43:33 -08:00
core-transaction.c firewire: fix use of multiple AV/C devices, allow multiple FCP listeners 2009-12-29 19:58:16 +01:00
core.h firewire: core: optimize Topology Map creation 2009-10-14 23:10:48 +02:00
Kconfig
Makefile
net.c
ohci.c firewire: ohci: always use packet-per-buffer mode for isochronous reception 2009-12-29 19:58:17 +01:00
ohci.h
sbp2.c firewire: normalize style of queue_work wrappers 2009-10-14 23:10:48 +02:00