Re: [PATCH net 2/2] r8152: rx descriptor check

From	David Miller <davem@davemloft.net>
Newsgroups	linux.kernel
Subject	Re: [PATCH net 2/2] r8152: rx descriptor check
Date	2016-11-14 18:30 +0100
Message-ID	<sDteV-1wp-27@gated-at.bofh.it> (permalink)
References	<sD74J-3nV-21@gated-at.bofh.it> <sD9Jg-5hc-13@gated-at.bofh.it> <sDjSh-3Rl-1@gated-at.bofh.it>
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From: Hayes Wang <hayeswang@realtek.com>
Date: Mon, 14 Nov 2016 07:23:51 +0000

> Mark Lord [mailto:mlord@pobox.com]
>> Sent: Monday, November 14, 2016 4:34 AM
> [...]
>> Perhaps the driver
>> is somehow accessing the buffer space again after doing usb_submit_urb()?
>> That would certainly produce this kind of behaviour.
> 
> I don't think so. First, the driver only read the received buffer.
> That is, the driver would not change (or write) the data. Second,
> The driver would lose the point address of the received buffer
> after submitting the urb to the USB host controller, until the
> transfer is completed by the USB host controller. That is, the
> driver doesn't how to access the buffer after calling usb_submit_urb().

This is why it's most likely some DMA implementation issue or similar.

Thread

Re: [PATCH net 2/2] r8152: rx descriptor check David Miller <davem@davemloft.net> - 2016-11-13 18:50 +0100
  Re: [PATCH net 2/2] r8152: rx descriptor check Mark Lord <mlord@pobox.com> - 2016-11-13 21:40 +0100
    Re: [PATCH net 2/2] r8152: rx descriptor check Mark Lord <mlord@pobox.com> - 2016-11-13 21:40 +0100
    RE: [PATCH net 2/2] r8152: rx descriptor check Hayes Wang <hayeswang@realtek.com> - 2016-11-14 08:30 +0100
      Re: [PATCH net 2/2] r8152: rx descriptor check David Miller <davem@davemloft.net> - 2016-11-14 18:30 +0100
  RE: [PATCH net 2/2] r8152: rx descriptor check Hayes Wang <hayeswang@realtek.com> - 2016-11-14 08:10 +0100

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