From: Mark Lord <mlord@pobox.com>
To: Greg KH <greg@kroah.com>
Cc: David Miller <davem@davemloft.net>,
hayeswang@realtek.com, netdev@vger.kernel.org,
nic_swsd@realtek.com, linux-kernel@vger.kernel.org,
linux-usb@vger.kernel.org
Subject: Re: [PATCH net 1/2] r8152: fix the sw rx checksum is unavailable
Date: Thu, 24 Nov 2016 14:10:36 -0500 [thread overview]
Message-ID: <9e8ff5b4-1c72-3106-7821-73484de133c2@pobox.com> (raw)
In-Reply-To: <20161124190055.GA3642@kroah.com>
On 16-11-24 02:00 PM, Greg KH wrote:
> On Thu, Nov 24, 2016 at 01:34:08PM -0500, Mark Lord wrote:
>> One thought: bulk data streams are byte streams, not packets.
>> Scheduling on the USB bus can break up larger transfers across
>> multiple in-kernel buffers. A "real" URB buffer on USB2 is max 512 bytes.
>> The driver is providing 16384-byte buffers, and assumes that data will
>> never spill over from one such buffer to the next.
>> Yet the observations here consistently show otherwise.
>
> Wait, how do you know that data will not spill over? What is making
> that guarantee? Will the USB device send a "zero packet" in order to
> show that all of the "logical" data is now sent for this specific
> endpoint? Is there some sort of "framing" that the device does with the
> USB data so that the driver "knows" where the end of packet is?
Exactly my point.
> Check the zero-packet stuff for this device, that's tripped up many a
> USB driver writer over the years, myself included.
I haven't tripped over it myself, but only because we were careful
to allow for such in the USB drivers I have worked on.
The r8152 driver just assumes it never happens.
next prev parent reply other threads:[~2016-11-24 19:10 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-11 7:15 [PATCH net 0/2] r8152: rx patches Hayes Wang
2016-11-11 7:15 ` [PATCH net 1/2] r8152: fix the sw rx checksum is unavailable Hayes Wang
2016-11-17 3:36 ` Hayes Wang
2016-11-17 14:14 ` Mark Lord
2016-11-17 14:25 ` Mark Lord
[not found] ` <d683c019-4e0f-6fe6-368c-c4fc86c72fe6@pobox.com>
2016-11-18 7:57 ` Hayes Wang
2016-11-18 12:03 ` Mark Lord
2016-11-22 13:12 ` Mark Lord
2016-11-23 3:52 ` Hayes Wang
2016-11-23 13:41 ` Mark Lord
2016-11-23 15:12 ` Hayes Wang
2016-11-23 19:29 ` Mark Lord
2016-11-24 3:24 ` Hayes Wang
2016-11-24 12:31 ` Mark Lord
2016-11-24 13:26 ` Hayes Wang
2016-11-24 15:24 ` Mark Lord
2016-11-25 6:11 ` Hayes Wang
2016-11-25 12:36 ` Mark Lord
2016-11-24 16:21 ` David Miller
2016-11-24 16:43 ` Mark Lord
2016-11-24 17:00 ` Mark Lord
2016-11-24 17:13 ` David Miller
2016-11-24 17:11 ` David Miller
2016-11-24 18:34 ` Mark Lord
2016-11-24 18:49 ` Mark Lord
2016-11-24 19:00 ` Greg KH
2016-11-24 19:10 ` Mark Lord [this message]
2016-11-24 19:17 ` Greg KH
2016-11-25 9:52 ` Hayes Wang
2016-11-25 13:32 ` Mark Lord
2016-11-25 0:27 ` Francois Romieu
2016-11-25 3:49 ` Mark Lord
2016-11-25 9:53 ` Greg KH
2016-11-25 12:34 ` Mark Lord
2016-11-25 12:41 ` Mark Lord
2016-11-25 14:22 ` Greg KH
2016-11-25 14:35 ` Mark Lord
2016-11-25 12:49 ` Mark Lord
2016-11-25 14:24 ` Greg KH
2016-11-25 16:58 ` David Miller
2016-11-30 11:58 ` Hayes Wang
2016-12-09 3:23 ` Hayes Wang
2016-12-09 13:05 ` Mark Lord
2017-01-01 0:07 ` Ansis Atteka
2017-01-03 0:40 ` Ansis Atteka
2017-01-03 13:19 ` Mark Lord
2017-01-09 7:58 ` Hayes Wang
2019-01-05 14:14 ` r8152: data corruption in various scenarios Mark Lord
2019-01-05 14:22 ` Mark Lord
2019-01-06 19:14 ` Kai Heng Feng
2019-01-06 21:13 ` Mark Lord
2019-01-06 21:16 ` Mark Lord
2019-01-07 3:53 ` Hayes Wang
2019-01-07 16:01 ` Mario.Limonciello
2019-01-07 18:06 ` Mark Lord
2019-01-07 18:27 ` Mario.Limonciello
2019-01-07 19:24 ` Mark Lord
2019-01-07 4:09 ` Kai Heng Feng
2019-01-07 4:13 ` Mark Lord
2019-01-07 6:46 ` Kai Heng Feng
2019-01-07 7:01 ` Mark Lord
2016-11-24 18:42 ` [PATCH net 1/2] r8152: fix the sw rx checksum is unavailable Greg KH
2016-11-24 18:58 ` Mark Lord
2016-11-25 6:31 ` Hayes Wang
2016-11-25 6:51 ` Hayes Wang
2016-11-25 12:35 ` Mark Lord
2016-11-24 16:19 ` David Miller
2016-11-24 12:37 ` Hayes Wang
2016-11-11 7:15 ` [PATCH net 2/2] r8152: rx descriptor check Hayes Wang
2016-11-11 12:13 ` Francois Romieu
2016-11-12 13:21 ` Mark Lord
2016-11-14 6:43 ` Hayes Wang
2016-11-15 1:10 ` Francois Romieu
2016-11-17 3:05 ` Hayes Wang
2016-11-13 17:39 ` David Miller
2016-11-13 20:34 ` Mark Lord
2016-11-13 20:38 ` Mark Lord
2016-11-14 7:23 ` Hayes Wang
2016-11-14 17:27 ` David Miller
2016-11-14 7:03 ` Hayes Wang
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