Messages in this thread | | | Date | Wed, 17 Nov 2004 21:56:02 +0100 | From | Jens Axboe <> | Subject | Re: PATCH (for comment): ide-cd possible race in PIO mode |
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On Wed, Nov 17 2004, Alan Cox wrote: > 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.
Ah I see, makes sense. I didn't think about the shared irq case.
-- Jens Axboe
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