Thread (18 messages) 18 messages, 4 authors, 2021-11-02

Re: [PATCH 1/2] i2c: virtio: disable timeout handling

From: Viresh Kumar <viresh.kumar@linaro.org>
Date: 2021-10-19 14:37:55
Also in: linux-i2c, lkml

On 19-10-21, 13:16, Greg KH wrote:
On Tue, Oct 19, 2021 at 03:12:03PM +0530, Viresh Kumar wrote:
quoted
On 19-10-21, 11:36, Greg KH wrote:
quoted
What is the "other side" here?  Is it something that you trust or not?
Other side can be a remote processor (for remoteproc over virtio or
something similar), or traditionally it can be host OS or host
firmware providing virtualisation to a Guest running Linux (this
driver). Or something else..

I would incline towards "we trust the other side" here.
That's in contradition with what other people seem to think the virtio
drivers are for, see this crazy thread for details about that:
	https://lore.kernel.org/all/20211009003711.1390019-1-sathyanarayanan.kuppuswamy@linux.intel.com/ (local)

You can "trust" the hardware, but also handle things when hardware is
broken, which is most often the case in the real world.
That's what I was worried about when I got you in, broken or hacked :)
So why is having a timeout a problem here?  If you have an overloaded
system, you want things to time out so that you can start to recover.

And if that hardware stops working?  Timeouts are good to have, why not
just bump it up a bit if you are running into it in a real-world
situation?
I think it is set to HZ currently, though I haven't tried big
transfers but I still get into some issues with Qemu based stuff.
Maybe we can bump it up to few seconds :)

-- 
viresh
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