Disabling an arbitrary device

[Attilio Rao]

Il 20 aprile 2012 19:18, Arnaud Lacombe <lacombar at gmail.com> ha scritto:
> Hi,
>
> On Fri, Apr 20, 2012 at 2:16 PM, Arnaud Lacombe <lacombar at gmail.com> wrote:
>> Hi,
>>
>> I will be bringing up an old thread there, but it would seem the
>> situation did not evolve in the past 9 years. I have a machine running
>> 7.1 whose UHCI controller is generating some interrupt storm:
>>
>> # vmstat -i
>> interrupt                          total       rate
>> irq4: sio0                          1328          2
>> irq19: uhci1+                   63514509      96380
>> [...]
>>
>> generating useless load on one CPU:
>>
>> # top -SH
>> last pid:  5223;  load averages:  0.00,  0.00,  0.00    up 0+00:17:21  13:10:35
>> 117 processes: 14 running, 79 sleeping, 24 waiting
>> CPU:  0.2% user,  0.0% nice,  0.2% system,  6.6% interrupt, 93.0% idle
>> Mem: 33M Active, 9348K Inact, 67M Wired, 400K Cache, 29M Buf, 2892M Free
>> [...]
>>   57 root          -64    -     0K     8K CPU0   0  11:59 86.57% irq19: uhci1+
>>
>> I thought I could use an hint to forbid uhci(4) attachment, ala:
>>
>> hint.uhci.0.disabled="1"
>> hint.uhci.1.disabled="1"
>>
>> in /boot/loader.conf. However, it would seem that what should be
>> usable with any arbitrary devices, ie. be an integral part of
>> device(9), has to be hardcoded in every driver, sad.
>>
> as for the usual "if you're not happy, please provide a patch":
>
> https://github.com/lacombar/freebsd/commit/30786d09b0cb441890cdc749ee5243238e81d2d8

I think a generalized kludge should really belong to
device_probe_child() rather than device_add_child_ordered().

When you have a tested patch against -CURRENT, can you please send to
freebsd-newbus@?

BTW, IIRC 7.x doesn't have the new USB stack, which means that you can
have caught easilly a driver bug there, did you consider switching at
least to 8.x kernel?

Thanks,
Attilio


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