Linux may have been causing USB disconnects

#1

Post by chalst » Thu, Aug 22, 2013, 10:02 AM UTC

Linux may have been causing USB disconnects
plus.google.com

Re: Linux may have been causing USB disconnects

#2

Post by bryanlarsen » Thu, Aug 22, 2013, 10:33 AM UTC

Note that this bug was found because the software engineer talked to a hardware engineer.

Props to Intel for hiring leading Linux developers and turning them loose.

Re: Linux may have been causing USB disconnects

#3

Post by annnnd » Thu, Aug 22, 2013, 10:40 AM UTC

Congrats! But how nobody analysed this bug for 8+ years is a bit of a mystery to me...

Re: Linux may have been causing USB disconnects

#4

Post by oakwhiz » Thu, Aug 22, 2013, 10:44 AM UTC

This is a very interesting type of bug that I have often seen cropping up around hardware interfaces in microcontrollers.

Re: Linux may have been causing USB disconnects

#5

Post by makomk » Thu, Aug 22, 2013, 10:44 AM UTC

Wait, if I'm reading this correctly there's no safe resume recovery time which can be guaranteed not to cause devices to drop off the bus. The kernel could wait 10 minutes and devices could still require more than that. That seems like a pretty major issue with the USB specification.

Re: Linux may have been causing USB disconnects

#6

Post by [deleted] » Thu, Aug 22, 2013, 10:49 AM UTC

[deleted]

Re: Linux may have been causing USB disconnects

#7

Post by Jugurtha » Thu, Aug 22, 2013, 10:49 AM UTC

Well, that's why you don't hardcode a magic value, nor do you continuously poll the state of a device and rely instead on interrupts: That's what they're made for.

Re: Linux may have been causing USB disconnects

#8

Post by kalleboo » Thu, Aug 22, 2013, 10:52 AM UTC

Be sure to check out the mailing list post linked from the G+ post which contains more technical details and proposed fixes http://marc.info/?l=linux-usb&m=137714769606183&w=2

Re: Linux may have been causing USB disconnects

#9

Post by rustynails » Thu, Aug 22, 2013, 10:56 AM UTC

Now can someone fix the embarrassing network bug in Linux. You know, where if you access a link to a network, or access an open networked path after 255 seconds or so ... You receive a network error. It still begs belief that such a fundamental aspect of Linux is broken ... When I show Linux to newbies and this fault occurs (ie. 100% of the time), I simply say "Linux isn't perfect ..." But inside, I cringe...

It occurs under all distros I've tried and it's been there for years. Even on different computers with different hardware...

Re: Linux may have been causing USB disconnects

#10

Post by alexchamberlain » Thu, Aug 22, 2013, 11:00 AM UTC

Jugurtha wrote: post #7

Well, that's why you don't hardcode a magic value, nor do you continuously poll the state of a device and rely instead on interrupts: That's what they're made for.

That's not entirely fair; standards are full of hard coded values.