Subject: Re: plan to merge cats and netwinder isa_machdep.c
To: None <Richard.Earnshaw@buzzard.freeserve.co.uk>
From: Izumi Tsutsui <email@example.com>
Date: 10/10/2002 23:19:40
In article <200210091912.g99JCS313995@buzzard.buzzard.freeserve.co.uk>
> > Furthermore, _isa_bus_dmamap_sync() does not handle cache coherency
> > at all, but it should do like arm/arm32/bus_dma.c.
> Hmm, interesting. Then it's a surprise that I get anything even
> resembling audio out of my soundblaster ISA card at all. Though this
> would possibly explain some of the break-up.
In general, data buffers are really large and data cache on SA is
small (16k), so it would not cause problem so often.
Buffers of descripters for bus-master devices are usually
allocated with BUS_DMAMAP_COHERENT, so cache flush is not
required so strictly (on arm, which handles BUS_DMAMAP_COHERENT).
Actually, the only problem that was caused by missing cache-flush in
my experience is fxp(4) driver, which allocates RX descriptors in mbufs.