Re: [PATCH v3 4/4] USBNET: ax88179_178a: enable tso if usb host supports sg dma

On Fri, Aug 9, 2013 at 8:18 AM, Grant Grundler [off-list ref] wrote:

Ming,
We are splitting hairs now. :) I want to be clear I think your changes
are good and the rest of this conversation is just to learn something
new.

On Thu, Aug 8, 2013 at 4:48 PM, Ming Lei [off-list ref] wrote:

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On Fri, Aug 9, 2013 at 1:25 AM, Grant Grundler [off-list ref] wrote:

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I am afraid that PCI network devices' setting still won't survive unbound&
re-probed, will they?

Correct - but PCI isn't as prone to "dropping off the bus" like USB

As far as I know, USB device still won't be disconnected easily, and
reset is possible, but we can make setting survive reset by implementing
.pre_reset() and .post_reset() callback. Or do you have other situation
of USB 'dropping off the bus'?

So far only older USB core bugs like this one:
    https://codereview.chromium.org/4687002/show

This happens in configuration change situation, which is seldom
triggered, and also not "randomly" happen per your standpoint,
just like rmmod/modprobe , :-)

I agree USB won't be disconnected easily.

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is. Master aborts on some PCI systems is a "Fatal Exception" and AFAIK
that's never been true for any USB device.

I mean rmmod & modprobe still can reset setting of one PCI network
device after powering on the device, can't it?

Definitely. But this isn't something that will "randomly" happen and
will leave tracks all over the place of it happening. So I'm not
worried about trying to debug this scenario.

Thanks,
--
Ming Lei