umass causes panic on 7 amd64

[Peter Jeremy]

On Thu, Apr 17, 2008 at 07:13:17PM -0400, Garrett Wollman wrote:
>In my experience, umass over EHCI has never worked on any machine
>ever, going back to 5.x and over multiple kinds of umass devices.  (I
>never saw panics, only triple-fault CPU resets.)

OTOH, I've had mixed results, though I haven't seen panics caused by
EHCI.  umass has a tendency to panic when it trips over an interface
bug between bus_dmamem_alloc(9) and contigmalloc(9) which has been
present since at least 4.x, though the work-arounds have improved and
this is less of a problem than it was 3 years ago.

On my laptop (HP nx6125, ATI SB400 chipset), I haven't had any problems
with EHCI in 6.x or 7.0 (both amd64 - I can't recall if I've tried ECHI
whilst running i386).

My son's laptop (HP V6107au, nVIDIA MCP51 chipset, 6.x/amd64) gives
varying results (sometimes it works, sometimes it doesn't) and he's
found that plugging flashdisks into the USB hub on his keyboard gives
better results than plugging them into the system (which doesn't make
sense to me - they still show a attached to EHCI).

My work desktop (Dell OptiPlex GX620, Intel ICH7 chipset 7.0/amd64)
refuses to acknowledge EHCI devices - it just reports timeouts and
disables that USB port.  [See my recent posting to -amd64].

-- 
Peter Jeremy
Please excuse any delays as the result of my ISP's inability to implement
an MTA that is either RFC2821-compliant or matches their claimed behaviour.
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