From: "Gérard Roudier" <groudier@free.fr>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Kent E Yoder <yoder1@us.ibm.com>,
Jeff Garzik <jgarzik@mandrakesoft.com>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] IBM Lanstreamer bugfixes
Date: Sat, 19 Jan 2002 00:52:02 +0100 (CET) [thread overview]
Message-ID: <20020119004144.F2500-100000@gerard> (raw)
In-Reply-To: <E16RiHs-0008CD-00@the-village.bc.nu>
On Fri, 18 Jan 2002, Alan Cox wrote:
> > BTW, I don't know what PCI posting effects are...
>
> Ok given
>
> writel(foo, dev->reg);
> udelay(5);
> writel(bar, dev->reg);
>
> The pci bridge is at liberty to delay the first write until the second or a
> read from that device comes along (and wants to do so to merge bursts). It
> tends to bite people
>
> - When they do a write to clear the IRQ status and don't do
> a read so they keep handling lots of phantom level triggered
> interrupts.
Not only (when the write is intended to clear some interrupt condition).
As the actual clear of the interrupt condition is delayed, then it may
just also clear a sub-sequent condition and this condition may be missed
by the driver interrupt routine. Due to this a race, interrupt stall can
occur.
> - When there is a delay (reset is common) that has to be observed
>
> - At the end of a DMA transfer when people unmap stuff early
> and the "stop the DMA" command got delayed
Gérard.
next prev parent reply other threads:[~2002-01-18 23:53 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-01-18 23:02 [PATCH] IBM Lanstreamer bugfixes Kent E Yoder
2002-01-18 23:19 ` Alan Cox
2002-01-18 23:52 ` Gérard Roudier [this message]
2002-01-19 17:14 ` Mike Phillips
-- strict thread matches above, loose matches on Subject: below --
2002-02-01 20:53 Kent E Yoder
2002-02-01 23:38 ` Alan Cox
2002-02-01 23:40 ` Alan Cox
2002-01-30 19:27 Kent E Yoder
2002-01-30 19:48 ` Jeff Garzik
2002-01-30 19:58 ` David Weinehall
2002-01-30 20:43 ` Alan Cox
2002-01-30 20:04 ` Mike Phillips
2002-01-30 20:47 ` Alan Cox
2002-01-21 16:44 Kent E Yoder
2002-01-21 17:46 ` Mike Phillips
2002-01-18 22:39 Kent E Yoder
2002-01-18 22:32 Kent E Yoder
2002-01-18 22:47 ` Alan Cox
2002-01-18 20:52 Kent E Yoder
2002-01-18 21:35 ` Alan Cox
2002-01-17 15:29 Kent E Yoder
2002-01-16 19:42 Kent E Yoder
2002-01-17 10:57 ` Jeff Garzik
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