Re: [patch] voluntary-preempt-2.6.9-rc2-mm1-S1

[Ingo Molnar <mingo@elte.hu>]

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* Shane Shrybman <shrybman@aei.ca> wrote:

> I am having what appears to be IDE DMA problems with 2.6.9-rc2-mm1-S1.
> 2.6.9-rc2-mm1 does not show this problem and runs fine. Before this I
> was happily using 2.6.8-rc3-O5.
> 
> I tried booting with acpi=off but was unable to enter my user name at
> the login prompt, it just hung with no response to sysreq. I also
> tried turning off irq threading for that irq but it made no
> difference.

does undoing (patch -R) the attached patch fix this IDE problem?

	Ingo

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--- linux/drivers/ide/ide-io.c.orig	
+++ linux/drivers/ide/ide-io.c	
@@ -114,6 +114,9 @@ static int __ide_end_request(ide_drive_t
 	int ret = 1;
 
 	BUG_ON(!(rq->flags & REQ_STARTED));
+	spin_unlock(&ide_lock);
+	if (drive->unmask)
+		local_irq_enable();
 
 	/*
 	 * if failfast is set on a request, override number of sectors and
@@ -135,6 +138,7 @@ static int __ide_end_request(ide_drive_t
 	}
 
 	if (!end_that_request_first(rq, uptodate, nr_sectors)) {
+		spin_lock_irq(&ide_lock);
 		add_disk_randomness(rq->rq_disk);
 
 		if (blk_rq_tagged(rq))
@@ -144,7 +148,8 @@ static int __ide_end_request(ide_drive_t
 		HWGROUP(drive)->rq = NULL;
 		end_that_request_last(rq);
 		ret = 0;
-	}
+	} else
+		spin_lock_irq(&ide_lock);
 	return ret;
 }