Re: [PATCH 1/1] NET: usb: Adding URB_ZERO_PACKET flag to usbnet.c

[Elina Pasheva <epasheva-ywE8TTl5eJHWpu6QEFMNjNBPR1lH4CV8@public.gmane.org>]

On Wed, 2010-04-07 at 14:14 -0700, David Brownell wrote:
> On Tuesday 06 April 2010, you wrote:
> Recall that the reason to avoid sending zero length packts
> (ZLPs) is that many systems don't cope well with them...
> 
> The ""don't cope well" can be at the hardware level,
> or drivers not limited to device firmware.  I've seen
> the failures be very context-dependent .... as in, one
> standalone ZLP might work, but mix it in with back-to-back
> delivery of other packets and trouble ensues...
>   
> In short, it's hard to know which combinations of
> hardware an firmware would need it .... versus which
> ones it would break.
> 
> ... and thus risky to try sending ZLPs through systems
> shere for many years) we've carefully avoided doing that.
> 
> 
> - Dave
> 
Hi Dave, 
Nice to hear your opinion on this matter. Are you recommending our patch
be retracted? If so, we can look at other ways to fix the problem when a
zero length packet is missing. 

Regards, 
Elina


 

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