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From: "Petr Vandrovec" <VANDROVE@vc.cvut.cz>
Organization: CC CTU Prague
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Date: Wed, 7 Feb 2001 20:40:21 MET-1
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Subject: Re: Promise, DMA and RAID5 problems running 2.4.1
CC: sajjad@vgkk.com (A.Sajjad Zaidi), linux-kernel@vger.kernel.org
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On  7 Feb 01 at 19:33, Alan Cox wrote:
> > It is known bug which I reported to Andre already. Open
> > drivers/ide/ide.c in favorite text editor, and replace strange
> > body of ide_delay_50ms() with simple mdelay(50). Promise driver
> > invokes ide_delay_50ms with interrupts disabled, so it freezes
> > here forever. If you have NMI watchdog, you'll get nice oopses.
> 
> Its a bug in the promise driver. ide_delay_50ms() is being friendly to the
> rest of the box. If the reset path for the promise cant be polite then it
> should use mdelay() itself.

Iff CONFIG_BLK_DEV_IDECS is set then yes, doing schedule is better.
But I do not see any benefit in doing

unsigned long timeout = jiffies + ((HZ + 19)/20) + 1;
while (0 < (signed long)(timeout - jiffies));

over

mdelay(50);

And on my box, busy while loop is executed, not schedule(HZ/20)...

                                                Thanks,
                                                    Petr Vandrovec
                                                    vandrove@vc.cvut.cz
                                                    
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