Panic Kernel Dump to umass device?

[Nate Nielsen]

Ian Dowse wrote:
> In message <43ED8E81.2060907 at samsco.org>, Scott Long writes:
> 
>>You're correct that dumping is meant to be done with interrupts and task
>>switching disabled.  The first thing that the umass driver is missing is
>>a working CAM poll handler.  Without this, there is no way for command
>>completions to be seen when interrupts are disabled.  Beyond that, I
>>somewhat suspect that the USB stack expects to be able to push command
>>completion work off to worker threads, at least for some situations, and
>>that also will not work in the kernel dump environment.  So, there is a
>>lot of work needed to make this happen.
> 
> 
> The USB stack supports polled operations, so it's actually not to
> hard to make this work. Below is a patch I had in one of my local
> trees that adds a CAM poll handler to the umass driver. I've just
> tested this and it does seem to make kernel dumping work, but I
> guess it might not be as reliable as dumping to other devices.

As noted earlier the umass polling patch you posted works for dumping to
a umass device via a uhci controller.

After a little more fiddling I've managed to get it working on an ohci
controller. Attached is a patch. This patch includes your patch above.

Cheers,
Nate
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