Date: Sun, 14 Jun 2009 10:27:31 +0300 From: Alexander Motin <mav@FreeBSD.org> To: rick-freebsd2008@kiwi-computer.com Cc: freebsd-multimedia@freebsd.org Subject: Re: snd_hda works on i386, fails on amd64 (RELENG_7) Message-ID: <4A34A663.2010503@FreeBSD.org> In-Reply-To: <20090614062157.GA67705@keira.kiwi-computer.com> References: <1242609781.00113421.1242598202@10.7.7.3> <4A122B72.80206@FreeBSD.org> <20090519184150.GA990@keira.kiwi-computer.com> <20090605020054.GA67365@keira.kiwi-computer.com> <4A28D79C.6070406@FreeBSD.org> <20090614050211.GA67556@keira.kiwi-computer.com> <20090614062157.GA67705@keira.kiwi-computer.com>
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Rick C. Petty wrote:
> On Fri, Jun 05, 2009 at 11:30:20AM +0300, Alexander Motin wrote:
>
>> Also you may try to change
>> sc->support_64bit = HDA_FLAG_MATCH(gcap, HDAC_GCAP_64OK);
>> line to
>> sc->support_64bit = 0;
>> , to strictly limit driver to 32bit addresses ignoring hardware
>> capabilities.
>
> Hmm, I looked at the place that queries support_64bit, in hdac_dma_alloc as
> part of the lowaddr to the bus_dma_tag_create(9) call:
>
> lowaddr = (sc->support_64bit) ? BUS_SPACE_MAXADDR :
> BUS_SPACE_MAXADDR_32BIT;
> ...
>
> On a whim, I tried manually setting lowaddr to BUS_SPACE_MAXADDR_24BIT and
> it worked! A binary search revealed that it breaks for me when
> lowaddr > 0x7FFFFFFF ... perhaps a 32-bit overflow bug related to DMA?
You are right. There is definitely overflow. Try this:
--- hdac.c.prev 2009-04-01 21:55:08.000000000 +0300
+++ hdac.c 2009-06-14 10:24:18.000000000 +0300
@@ -1589,9 +1589,9 @@ hdac_dma_cb(void *callback_arg, bus_dma_
static int
hdac_dma_alloc(struct hdac_softc *sc, struct hdac_dma *dma, bus_size_t
size)
{
+ bus_addr_t lowaddr;
bus_size_t roundsz;
int result;
- int lowaddr;
roundsz = roundup2(size, HDAC_DMA_ALIGNMENT);
lowaddr = (sc->support_64bit) ? BUS_SPACE_MAXADDR :
--
Alexander Motin
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