From 5100d5ac81b9330dc57e35adbe50923ba6107b8f Mon Sep 17 00:00:00 2001 From: Michael Buesch Date: Sat, 29 Mar 2008 21:01:16 +0100 Subject: b43: Add PIO support for PCMCIA devices This adds PIO support back (D'oh!) for PCMCIA devices. This is a complete rewrite of the old PIO code. It does actually work and we get reasonable performance out of it on a modern machine. On a PowerBook G4 I get a few MBit for TX and a few more for RX. So it doesn't work as well as DMA (of course), but it's a _lot_ faster than the old PIO code (only got a few kBit with that). The limiting factor is the host CPU speed. So it will generate 100% CPU usage when the network interface is heavily loaded. A voluntary preemption point in the RX path makes sure Desktop Latency isn't hurt. PIO is needed for 16bit PCMCIA devices, as we really don't want to poke with the braindead DMA mechanisms on PCMCIA sockets. Additionally, not all PCMCIA sockets do actually support DMA in 16bit mode (mine doesn't). Signed-off-by: Michael Buesch Signed-off-by: John W. Linville --- drivers/net/wireless/b43/Kconfig | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'drivers/net/wireless/b43/Kconfig') diff --git a/drivers/net/wireless/b43/Kconfig b/drivers/net/wireless/b43/Kconfig index 8bc4bc4..94f0455 100644 --- a/drivers/net/wireless/b43/Kconfig +++ b/drivers/net/wireless/b43/Kconfig @@ -62,6 +62,13 @@ config B43_PCMCIA If unsure, say N. +# Data transfers to the device via PIO +# This is only needed on PCMCIA devices. All others can do DMA properly. +config B43_PIO + bool + depends on B43 && (B43_PCMCIA || B43_FORCE_PIO) + default y + config B43_NPHY bool "Pre IEEE 802.11n support (BROKEN)" depends on B43 && EXPERIMENTAL && BROKEN @@ -94,3 +101,13 @@ config B43_DEBUG Say Y, if you want to find out why the driver does not work for you. + +config B43_FORCE_PIO + bool "Force usage of PIO instead of DMA" + depends on B43 && B43_DEBUG + ---help--- + This will disable DMA and always enable PIO instead. + + Say N! + This is only for debugging the PIO engine code. You do + _NOT_ want to enable this. -- cgit v1.1