From owner-freebsd-current@FreeBSD.ORG  Wed Mar 16 18:48:57 2005
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Date: Thu, 17 Mar 2005 00:48:54 +0600
From: Max Khon <fjoe@samodelkin.net>
To: Doug White <dwhite@gumbysoft.com>
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cc: freebsd-current@freebsd.org
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Subject: Re: ATAng: reboot after panic, crashdumps [PATCH]
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Hi!

On Wed, Mar 16, 2005 at 10:11:58AM -0800, Doug White wrote:

> > Attached patch fixes reboot after panic for me on RELENG_5 and RELENG_5_3.
> > Crashdumps work again for me as well.
> >
> > The problem was in ata_shutdown() -- ATA_FLUSHCACHE request issued from
> > ata_shutdown() never completes (ata_queue_request() sleeps in
> > sema_wait(&request->done)) because ata_interrupt() is never called
> > (callouts do not work as well, so that if the controller is busy
> > ATA_FLUSHCACHE was not retried).
> >
> > I am not sure if "if (panicstr == NULL)" check is required (for normal
> > shutdown sequence). addump() does not check if we are shutting down
> > cleanly (ata_flushcache() was copy-n-pasted from addump()) and always
> > uses atadev->channel->hw.begin_transaction(&request)/end_transaction(&request)
> > directly.
> 
> This part here:
> 
> +    if (atadev->channel->hw.begin_transaction(&request) ==
> ATA_OP_CONTINUES) {
> +       do {
> +           DELAY(20);
> +       } while (atadev->channel->hw.end_transaction(&request) ==
> ATA_OP_CONTINUES);
> 
> looks like it could get stuck in an infinite loop if the controller is
> hung.  I'm not familiar with the ata code so i don't nkow if this is
> handled elsewhere, but I figure I'd ask :)

This part is exactly what addump() does.

/fjoe