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

[Ming Lei <ming.lei@canonical.com>]

On Fri, Aug 9, 2013 at 8:18 AM, Grant Grundler <grundler@google.com> 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 <ming.lei@canonical.com> wrote:
>> On Fri, Aug 9, 2013 at 1:25 AM, Grant Grundler <grundler@google.com> wrote:
> ...
>>>> 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.
>
>>> 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