Date: Mon, 15 Dec 2014 01:22:11 -0800 From: =?utf-8?Q?Ask_Bj=C3=B8rn_Hansen?= <ask@develooper.com> To: Neel Natu <neelnatu@gmail.com> Cc: "freebsd-virtualization@freebsd.org" <freebsd-virtualization@freebsd.org> Subject: Re: Unsupported cmd:c4 (ada0:ahcich0:0:0:0): READ_MUL. ACB: c4 00 00 00 00 40 00 00 00 00 01 00 Message-ID: <9AF2F3EC-E54D-49D6-A9E0-AB3163CEFCB2@develooper.com> In-Reply-To: <CAFgRE9F5bC4t6sDRtKVRLD0kLeLFWi%2B1kK5Jx5c8RZHYh5LyUA@mail.gmail.com> References: <C47B8B4E-5127-4121-BC73-2B4E6129652B@develooper.com> <CAFgRE9F5bC4t6sDRtKVRLD0kLeLFWi%2B1kK5Jx5c8RZHYh5LyUA@mail.gmail.com>
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[ It looks like I didn't send this earlier ]
> Are you, by any chance, setting the tunable 'hw.ata.ata_dma' to 0 to
> disable DMA?
>
> I ask this because in the dmesg above you have:
> ada0: 300.000MB/s transfers (SATA 2.x, PIO4, PIO 8192bytes)
>
> In my setup, I get this instead:
> ada0: 300.000MB/s transfers (SATA 2.x, UDMA6, PIO 8192bytes)
Hi Neel,
Good eyes, indeed I do! Very nice.
# grep -rh ata_dma .
echo 'hw.ata.ata_dma="0"' >> boot/device.hints
My VCS log says I added it 6 years ago -- "disable DMA for better Soekris/Alix support”, which probably seemed like a very specific commit message at the time. For what it's worth the system is booting fine without the setting on my alix and soekris boards, too.
Thank you!
The ZFS devmode didn't seem to make a difference for this; but setting it to 'dev' did fix some warnings I was getting when making snapshots, so that was useful too. Thank you, Allan.
Ask
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