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From: "'Roger Luethi'" <rl@hellgate.ch>
To: Manfred Spraul <manfred@colorfullife.com>
Cc: linux-kernel@vger.kernel.org, Shing Chuang <ShingChuang@via.com.tw>
Subject: Re: [PATCH] #2 VIA Rhine stalls: TxAbort handling
Date: Fri, 17 May 2002 21:56:03 +0200	[thread overview]
Message-ID: <20020517195603.GA7681@k3.hellgate.ch> (raw)
In-Reply-To: <3CE55009.9050505@colorfullife.com>

> >>do {} while (BYTE_REG_BITS_IS_ON(CR0_TXON,&pMacRegs->byCR0));
> >
> >The driver "waits a little" in the interrupt handler? How long can that
> >take, worst case? I don't know of many places where the kernel stops to
> >wait for an external device to change some value.
> 
> It's not that uncommon: Most network drivers busy-wait after stopping 
> the tx process during netif_close().

Yeah, but they don't depend on the chip to behave. They will break out at
some point. That's the issue several people pointed out.

> Shing, I don't like the empty body of the while loop. It's not a bug, 
> but doesn't that generate a large load on the pci bus?
> 
> I've always added an udelay(1), i.e. wait one microsecond, into such loops.

Sounds reasonable. I will add that later. Currently I have no delay,
either, because I want to collect some numbers about how long we expect to
wait.

Roger

  reply	other threads:[~2002-05-17 19:56 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-05-17 18:46 [PATCH] #2 VIA Rhine stalls: TxAbort handling Manfred Spraul
2002-05-17 19:56 ` 'Roger Luethi' [this message]
2002-05-18 10:08 ` David Woodhouse
     [not found] <369B0912E1F5D511ACA5003048222B75A3C06E@EXCHANGE2>
     [not found] ` <20020518040143.GA9318@k3.hellgate.ch>
2002-05-17 23:13   ` Ivan G.
2002-05-18 19:11     ` 'Roger Luethi'
  -- strict thread matches above, loose matches on Subject: below --
2002-05-16 10:03 Shing Chuang
2002-05-16 18:03 ` 'Roger Luethi'
2002-05-16 18:25   ` Richard B. Johnson
2002-05-16 20:31     ` 'Roger Luethi'
2002-05-16 16:39       ` Ivan G.
2002-05-16 21:05       ` Richard B. Johnson
2002-05-17  0:16         ` 'Roger Luethi'
2002-05-17 12:51           ` Richard B. Johnson
2002-05-17 16:25             ` 'Roger Luethi'
2002-05-16  3:13 Roger Luethi

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