From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paul Mackerras <paulus@samba.org>
Subject: Re: [Bugme-new] [Bug 6530] New: MAINLINE
Date: Thu, 11 May 2006 14:01:54 +1000
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	xeb@mail.ru
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To: Andrew Morton <akpm@osdl.org>
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Andrew Morton writes:

> xeb has said:
> 
> in this construction:
> 
>           if ((test_bit(XMIT_WAKEUP, &ap->xmit_flags) ||
>              test_bit(XMIT_FULL, &ap->xmit_flags)) && ppp_async_push(ap))
>                   ppp_output_wakeup(&ap->chan);
> 
> if ppp_async_push() doesn't send any data i.e.  XMIT_FULL is set then all
> (transfer) hangs up while somebody push again, for instance lcp-echo.  

If XMIT_FULL and ppp_async_push doesn't send any data, that means the
serial driver's output buffer was full.  If that's the case, *and* we
don't see a call to ppp_output_wakeup, then the finger points squarely
at the serial driver as the source of the bug.

Paul.