Date: Sun, 14 Jun 2009 01:21:57 -0500 From: "Rick C. Petty" <rick-freebsd2008@kiwi-computer.com> To: Alexander Motin <mav@FreeBSD.org> Cc: freebsd-multimedia@freebsd.org Subject: Re: snd_hda works on i386, fails on amd64 (RELENG_7) Message-ID: <20090614062157.GA67705@keira.kiwi-computer.com> In-Reply-To: <20090614050211.GA67556@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>
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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? Out of curiosity, how come this same test (for support_64bit) isn't needed before the bus_dma_tag_create() in hdac_attach? -- Rick C. Petty
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