Messages in this thread | | | Subject | Re: PATCH (for comment): ide-cd possible race in PIO mode | From | Alan Cox <> | Date | Wed, 17 Nov 2004 16:25:30 +0000 |
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On Mer, 2004-11-17 at 15:37, Jens Axboe wrote: > > - HWIF(drive)->OUTB(WIN_PACKETCMD, IDE_COMMAND_REG); > > + spin_lock_irqsave(&ide_lock, flags); > > + HWIF(drive)->OUTBSYNC(WIN_PACKETCMD, IDE_COMMAND_REG); > > + ndelay(400); > > + spin_unlock_irqsave(&ide_lock, flags); > > return (*handler) (drive); > > } > > } > > What good does the lock do?
The same as in ide_execute_command - make sure we don't take an IDE interrupt that tries to read the state during the delay. That is the old 2.4 "may drives shared IRQ random fails" fix and why the lock is taken in ide_execute_command.
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