forked from Minki/linux
a186b4a6b2
Third rendition of FireWire OHCI 1.0 Isochronous Receive support, using a zer-copy method similar to OHCI 1.1 which puts the IR data payload directly into the userspace buffer. The zero-copy implementation eliminates the video artifacts, audio popping, and buffer underrun problems seen with version 1 of this patch, as well as fixing a regression in OHCI 1.1 support introduced by version 2 of this patch. Successfully tested in OHCI 1.1 mode on the following chipsets: - NEC uPD72847 (rev 01), OHCI 1.1 (PCI) - Ti XIO2200(A) (rev 01), OHCI 1.1 (PCIe) - Ti TSB41AB2 (rev 01), OHCI 1.1 (PCI on SB Audigy) - Apple UniNorth 2 (rev 81), OHCI 1.1 (PowerBook G4 onboard) Successfully tested in OHCI 1.0 mode on the following chipsets: - Agere FW323 (rev 06), OHCI 1.0 (Mac Mini onboard) - Agere FW323 (rev 06), OHCI 1.0 (PCI) - Via VT6306 (rev 46), OHCI 1.0 (PCI) - NEC OrangeLink (rev 01), OHCI 1.0 (PCI) - NEC uPD72847 (rev 01), OHCI 1.1 (PCI) - Ti XIO2200(A) (rev 01), OHCI 1.1 (PCIe) The bulk of testing was done in an x86_64 system, but was also successfully sanity-tested on other systems, including a PPC(32) PowerBook G4 and an i686 EPIA M10k. Crude benchmarking (watching top during capture) puts the cpu utilization during capture on the EPIA's 1GHz Via C3 processor around 13%, which is down from 30% with the v1 code. Some implementation details: To maintain the same userspace API as dual-buffer mode, we set up two descriptors for every incoming packet. The first is an INPUT_MORE descriptor, pointing to a buffer large enough to hold just the packet's iso headers, immediately followed by an INPUT_LAST descriptor, pointing to a chunk of the userspace buffer big enough for the packet's data payload. With this setup, each incoming packet fills in these two descriptors in a manner that very closely emulates dual-buffer receive, to the point where the bulk of the handle_ir_* code is now identical between the two (and probably primed for some restructuring to share code between them). The only caveat I have at the moment is that neither of my OHCI 1.0 Via VT6307-based FireWire controllers work particularly well with this code for reasons I have yet to figure out. Signed-off-by: Jarod Wilson <jwilson@redhat.com> Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de> |
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| .. | ||
| fw-card.c | ||
| fw-cdev.c | ||
| fw-device.c | ||
| fw-device.h | ||
| fw-iso.c | ||
| fw-ohci.c | ||
| fw-ohci.h | ||
| fw-sbp2.c | ||
| fw-topology.c | ||
| fw-topology.h | ||
| fw-transaction.c | ||
| fw-transaction.h | ||
| Kconfig | ||
| Makefile | ||