[PATCH] Fix floppy hibernation

[PATCH] Fix floppy hibernation

[Ondrej Zary]

Hello,
floppy driver was always missing hibernation support. After resume, floppy did
not work (until a couple of disk reinserts and retries), producing errors like
this:
end_request: I/O error, dev fd0, sector 0

Ingo Molnar tried to fix it in 2006: http://lkml.org/lkml/2006/11/12/92




Based on Ingo Molnar's patch from 2006, this makes the floppy work after
resume from hibernation, at least on my machine.


Signed-off-by: Ondrej Zary <linux@rainbow-software.org>

--- linux-2.6.29.4-orig/drivers/block/floppy.c	2009-05-30 14:38:29.000000000 +0200
+++ linux/drivers/block/floppy.c	2009-05-30 17:50:32.000000000 +0200
@@ -4148,6 +4148,24 @@
 {
 }
 
+static int floppy_resume(struct platform_device *dev)
+{
+	int i;
+
+	for (i = 0; i < N_FDC; i++)
+		if (FDCS->address != -1)
+			user_reset_fdc(-1, FD_RESET_ALWAYS, 0);
+
+	return 0;
+}
+
+static struct platform_driver floppy_driver = {
+	.resume = floppy_resume,
+	.driver = {
+		.name = "floppy",
+	},
+};
+
 static struct platform_device floppy_device[N_DRIVE];
 
 static struct kobject *floppy_find(dev_t dev, int *part, void *data)
@@ -4196,10 +4214,14 @@
 	if (err)
 		goto out_put_disk;
 
+	err = platform_driver_register(&floppy_driver);
+	if (err)
+		goto out_unreg_blkdev;
+
 	floppy_queue = blk_init_queue(do_fd_request, &floppy_lock);
 	if (!floppy_queue) {
 		err = -ENOMEM;
-		goto out_unreg_blkdev;
+		goto out_unreg_driver;
 	}
 	blk_queue_max_sectors(floppy_queue, 64);
 
@@ -4346,6 +4368,8 @@
 out_unreg_region:
 	blk_unregister_region(MKDEV(FLOPPY_MAJOR, 0), 256);
 	blk_cleanup_queue(floppy_queue);
+out_unreg_driver:
+	platform_driver_unregister(&floppy_driver);
 out_unreg_blkdev:
 	unregister_blkdev(FLOPPY_MAJOR, "fd");
 out_put_disk:
@@ -4566,6 +4590,7 @@
 
 	blk_unregister_region(MKDEV(FLOPPY_MAJOR, 0), 256);
 	unregister_blkdev(FLOPPY_MAJOR, "fd");
+	platform_driver_unregister(&floppy_driver);
 
 	for (drive = 0; drive < N_DRIVE; drive++) {
 		del_timer_sync(&motor_off_timer[drive]);


-- 
Ondrej Zary

Re: [PATCH] Fix floppy hibernation

[Pavel Machek]

On Sat 2009-05-30 18:04:25, Ondrej Zary wrote:
> Hello,
> floppy driver was always missing hibernation support. After resume, floppy did
> not work (until a couple of disk reinserts and retries), producing errors like
> this:
> end_request: I/O error, dev fd0, sector 0
> 
> Ingo Molnar tried to fix it in 2006: http://lkml.org/lkml/2006/11/12/92
> 
> 
> 
> 
> Based on Ingo Molnar's patch from 2006, this makes the floppy work after
> resume from hibernation, at least on my machine.
> 
> 
> Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Acked-by: Pavel Machek <pavel@ucw.cz>


-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

Re: [PATCH] Fix floppy hibernation

[Ingo Molnar]

* Pavel Machek <pavel@ucw.cz> wrote:

> On Sat 2009-05-30 18:04:25, Ondrej Zary wrote:
> > Hello,
> > floppy driver was always missing hibernation support. After resume, floppy did
> > not work (until a couple of disk reinserts and retries), producing errors like
> > this:
> > end_request: I/O error, dev fd0, sector 0
> > 
> > Ingo Molnar tried to fix it in 2006: http://lkml.org/lkml/2006/11/12/92
> > 
> > 
> > 
> > 
> > Based on Ingo Molnar's patch from 2006, this makes the floppy work after
> > resume from hibernation, at least on my machine.
> > 
> > 
> > Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
> Acked-by: Pavel Machek <pavel@ucw.cz>

nice patch ... thanks for picking up what i left unfinished.

	Ingo

Re: [PATCH] Fix floppy hibernation

[Rafael J. Wysocki]

On Monday 01 June 2009, Ingo Molnar wrote:
> 
> * Pavel Machek <pavel@ucw.cz> wrote:
> 
> > On Sat 2009-05-30 18:04:25, Ondrej Zary wrote:
> > > Hello,
> > > floppy driver was always missing hibernation support. After resume, floppy did
> > > not work (until a couple of disk reinserts and retries), producing errors like
> > > this:
> > > end_request: I/O error, dev fd0, sector 0
> > > 
> > > Ingo Molnar tried to fix it in 2006: http://lkml.org/lkml/2006/11/12/92
> > > 
> > > 
> > > 
> > > 
> > > Based on Ingo Molnar's patch from 2006, this makes the floppy work after
> > > resume from hibernation, at least on my machine.
> > > 
> > > 
> > > Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
> > Acked-by: Pavel Machek <pavel@ucw.cz>
> 
> nice patch ... thanks for picking up what i left unfinished.

I guess I'll take it to the suspend tree.  Or is it a better place?

Best,
Rafael

Re: [PATCH] Fix floppy hibernation

[Ingo Molnar]

* Rafael J. Wysocki <rjw@sisk.pl> wrote:

> On Monday 01 June 2009, Ingo Molnar wrote:
> > 
> > * Pavel Machek <pavel@ucw.cz> wrote:
> > 
> > > On Sat 2009-05-30 18:04:25, Ondrej Zary wrote:
> > > > Hello,
> > > > floppy driver was always missing hibernation support. After resume, floppy did
> > > > not work (until a couple of disk reinserts and retries), producing errors like
> > > > this:
> > > > end_request: I/O error, dev fd0, sector 0
> > > > 
> > > > Ingo Molnar tried to fix it in 2006: http://lkml.org/lkml/2006/11/12/92
> > > > 
> > > > 
> > > > 
> > > > 
> > > > Based on Ingo Molnar's patch from 2006, this makes the floppy work after
> > > > resume from hibernation, at least on my machine.
> > > > 
> > > > 
> > > > Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
> > > Acked-by: Pavel Machek <pavel@ucw.cz>
> > 
> > nice patch ... thanks for picking up what i left unfinished.
> 
> I guess I'll take it to the suspend tree.  Or is it a better 
> place?

Sounds like a good idea.

	Ingo

Re: [PATCH] Fix floppy hibernation

[Andrew Morton]

On Sat, 30 May 2009 18:04:25 +0200
Ondrej Zary <linux@rainbow-software.org> wrote:

> Hello,
> floppy driver was always missing hibernation support. After resume, floppy did
> not work (until a couple of disk reinserts and retries), producing errors like
> this:
> end_request: I/O error, dev fd0, sector 0
> 
> Ingo Molnar tried to fix it in 2006: http://lkml.org/lkml/2006/11/12/92
> 
> 
> 
> 
> Based on Ingo Molnar's patch from 2006, this makes the floppy work after
> resume from hibernation, at least on my machine.
> 
> 
> Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
> 
> --- linux-2.6.29.4-orig/drivers/block/floppy.c	2009-05-30 14:38:29.000000000 +0200
> +++ linux/drivers/block/floppy.c	2009-05-30 17:50:32.000000000 +0200
> @@ -4148,6 +4148,24 @@
>  {
>  }
>  
> +static int floppy_resume(struct platform_device *dev)
> +{
> +	int i;
> +
> +	for (i = 0; i < N_FDC; i++)
> +		if (FDCS->address != -1)
> +			user_reset_fdc(-1, FD_RESET_ALWAYS, 0);
> +
> +	return 0;
> +}

hm, how does this work?

FDCS is a revolting should-not-exist macro which assumes the presence
of a local variable called `fdc'.

So I think the loop control variable here should be called `fdc', not `i'.

It's pretty amazing that something like this still exists in a core
driver.  Someone please save us!

Re: [PATCH] Fix floppy hibernation

[Ondrej Zary]

On Tuesday 02 June 2009 01:45:20 Andrew Morton wrote:
> On Sat, 30 May 2009 18:04:25 +0200
>
> Ondrej Zary <linux@rainbow-software.org> wrote:
> > Hello,
> > floppy driver was always missing hibernation support. After resume,
> > floppy did not work (until a couple of disk reinserts and retries),
> > producing errors like this:
> > end_request: I/O error, dev fd0, sector 0
> >
> > Ingo Molnar tried to fix it in 2006: http://lkml.org/lkml/2006/11/12/92
> >
> >
> >
> >
> > Based on Ingo Molnar's patch from 2006, this makes the floppy work after
> > resume from hibernation, at least on my machine.
> >
> >
> > Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
> >
> > --- linux-2.6.29.4-orig/drivers/block/floppy.c	2009-05-30
> > 14:38:29.000000000 +0200 +++ linux/drivers/block/floppy.c	2009-05-30
> > 17:50:32.000000000 +0200 @@ -4148,6 +4148,24 @@
> >  {
> >  }
> >
> > +static int floppy_resume(struct platform_device *dev)
> > +{
> > +	int i;
> > +
> > +	for (i = 0; i < N_FDC; i++)
> > +		if (FDCS->address != -1)
> > +			user_reset_fdc(-1, FD_RESET_ALWAYS, 0);
> > +
> > +	return 0;
> > +}
>
> hm, how does this work?
>
> FDCS is a revolting should-not-exist macro which assumes the presence
> of a local variable called `fdc'.

The driver is complete mess - there is also a global static fdc variable.
So it worked because I have only one floppy controller.

> So I think the loop control variable here should be called `fdc', not `i'.

See the v2 patch below. Tested and works too.

>
> It's pretty amazing that something like this still exists in a core
> driver.  Someone please save us!




Based on Ingo Molnar's patch from 2006, this makes the floppy work after
resume from hibernation, at least on my machine.


Signed-off-by: Ondrej Zary <linux@rainbow-software.org>

--- linux-2.6.29.4-orig/drivers/block/floppy.c	2009-05-30 14:38:29.000000000 +0200
+++ linux/drivers/block/floppy.c	2009-06-02 17:32:56.000000000 +0200
@@ -4148,6 +4148,24 @@
 {
 }
 
+static int floppy_resume(struct platform_device *dev)
+{
+	int fdc;
+
+	for (fdc = 0; fdc < N_FDC; fdc++)
+		if (FDCS->address != -1)
+			user_reset_fdc(-1, FD_RESET_ALWAYS, 0);
+
+	return 0;
+}
+
+static struct platform_driver floppy_driver = {
+	.resume = floppy_resume,
+	.driver = {
+		.name = "floppy",
+	},
+};
+
 static struct platform_device floppy_device[N_DRIVE];
 
 static struct kobject *floppy_find(dev_t dev, int *part, void *data)
@@ -4196,10 +4214,14 @@
 	if (err)
 		goto out_put_disk;
 
+	err = platform_driver_register(&floppy_driver);
+	if (err)
+		goto out_unreg_blkdev;
+
 	floppy_queue = blk_init_queue(do_fd_request, &floppy_lock);
 	if (!floppy_queue) {
 		err = -ENOMEM;
-		goto out_unreg_blkdev;
+		goto out_unreg_driver;
 	}
 	blk_queue_max_sectors(floppy_queue, 64);
 
@@ -4346,6 +4368,8 @@
 out_unreg_region:
 	blk_unregister_region(MKDEV(FLOPPY_MAJOR, 0), 256);
 	blk_cleanup_queue(floppy_queue);
+out_unreg_driver:
+	platform_driver_unregister(&floppy_driver);
 out_unreg_blkdev:
 	unregister_blkdev(FLOPPY_MAJOR, "fd");
 out_put_disk:
@@ -4566,6 +4590,7 @@
 
 	blk_unregister_region(MKDEV(FLOPPY_MAJOR, 0), 256);
 	unregister_blkdev(FLOPPY_MAJOR, "fd");
+	platform_driver_unregister(&floppy_driver);
 
 	for (drive = 0; drive < N_DRIVE; drive++) {
 		del_timer_sync(&motor_off_timer[drive]);

-- 
Ondrej Zary

Re: [PATCH] Fix floppy hibernation

[Andrew Morton]

On Tue, 2 Jun 2009 18:30:50 +0200
Ondrej Zary <linux@rainbow-software.org> wrote:

> > > +static int floppy_resume(struct platform_device *dev)
> > > +{
> > > +	int i;
> > > +
> > > +	for (i = 0; i < N_FDC; i++)
> > > +		if (FDCS->address != -1)
> > > +			user_reset_fdc(-1, FD_RESET_ALWAYS, 0);
> > > +
> > > +	return 0;
> > > +}
> >
> > hm, how does this work?
> >
> > FDCS is a revolting should-not-exist macro which assumes the presence
> > of a local variable called `fdc'.
> 
> The driver is complete mess - there is also a global static fdc variable.
> So it worked because I have only one floppy controller.
> 
> > So I think the loop control variable here should be called `fdc', not `i'.
> 
> See the v2 patch below. Tested and works too.

OK.

> >
> > It's pretty amazing that something like this still exists in a core
> > driver.  Someone please save us!
> 
> 
> 
> 
> Based on Ingo Molnar's patch from 2006, this makes the floppy work after
> resume from hibernation, at least on my machine.
> 

That's a very skimpy changelog.  The lack of any useful reference to
the referred-to Ingopatch doesn't aid things..

> --- linux-2.6.29.4-orig/drivers/block/floppy.c	2009-05-30 14:38:29.000000000 +0200
> +++ linux/drivers/block/floppy.c	2009-06-02 17:32:56.000000000 +0200
> @@ -4148,6 +4148,24 @@
>  {
>  }
>  
> +static int floppy_resume(struct platform_device *dev)
> +{
> +	int fdc;
> +
> +	for (fdc = 0; fdc < N_FDC; fdc++)
> +		if (FDCS->address != -1)
> +			user_reset_fdc(-1, FD_RESET_ALWAYS, 0);
> +
> +	return 0;
> +}

The patch changes the driver so that it calls user_reset_fdc() for each
device at resume-time.

Why?  What effect does this have on the hardware and why does it fix things?

Thanks.

Re: [PATCH] Fix floppy hibernation

[Ondrej Zary]

On Wednesday 03 June 2009, Andrew Morton wrote:
> On Tue, 2 Jun 2009 18:30:50 +0200
>
> Ondrej Zary <linux@rainbow-software.org> wrote:
> > > > +static int floppy_resume(struct platform_device *dev)
> > > > +{
> > > > +	int i;
> > > > +
> > > > +	for (i = 0; i < N_FDC; i++)
> > > > +		if (FDCS->address != -1)
> > > > +			user_reset_fdc(-1, FD_RESET_ALWAYS, 0);
> > > > +
> > > > +	return 0;
> > > > +}
> > >
> > > hm, how does this work?
> > >
> > > FDCS is a revolting should-not-exist macro which assumes the presence
> > > of a local variable called `fdc'.
> >
> > The driver is complete mess - there is also a global static fdc variable.
> > So it worked because I have only one floppy controller.
> >
> > > So I think the loop control variable here should be called `fdc', not
> > > `i'.
> >
> > See the v2 patch below. Tested and works too.
>
> OK.
>
> > > It's pretty amazing that something like this still exists in a core
> > > driver.  Someone please save us!
> >
> > Based on Ingo Molnar's patch from 2006, this makes the floppy work after
> > resume from hibernation, at least on my machine.
>
> That's a very skimpy changelog.  The lack of any useful reference to
> the referred-to Ingopatch doesn't aid things..
>
> > --- linux-2.6.29.4-orig/drivers/block/floppy.c	2009-05-30
> > 14:38:29.000000000 +0200 +++ linux/drivers/block/floppy.c	2009-06-02
> > 17:32:56.000000000 +0200 @@ -4148,6 +4148,24 @@
> >  {
> >  }
> >
> > +static int floppy_resume(struct platform_device *dev)
> > +{
> > +	int fdc;
> > +
> > +	for (fdc = 0; fdc < N_FDC; fdc++)
> > +		if (FDCS->address != -1)
> > +			user_reset_fdc(-1, FD_RESET_ALWAYS, 0);
> > +
> > +	return 0;
> > +}
>
> The patch changes the driver so that it calls user_reset_fdc() for each
> device at resume-time.
>
> Why?  What effect does this have on the hardware and why does it fix
> things?

I don't know at all, it's complete guesswork. The first thing I tested was 
rmmod floppy && modprobe floppy after resume - it worked. Narrowing the 
initialization code down resulted in this patch.

-- 
Ondrej Zary

Re: [PATCH] Fix floppy hibernation

[Andrew Morton]

On Wed, 3 Jun 2009 08:13:26 +0200 Ondrej Zary <linux@rainbow-software.org> wrote:

> > > +static int floppy_resume(struct platform_device *dev)
> > > +{
> > > +	int fdc;
> > > +
> > > +	for (fdc = 0; fdc < N_FDC; fdc++)
> > > +		if (FDCS->address != -1)
> > > +			user_reset_fdc(-1, FD_RESET_ALWAYS, 0);
> > > +
> > > +	return 0;
> > > +}
> >
> > The patch changes the driver so that it calls user_reset_fdc() for each
> > device at resume-time.
> >
> > Why?  What effect does this have on the hardware and why does it fix
> > things?
> 
> I don't know at all, it's complete guesswork. The first thing I tested was 
> rmmod floppy && modprobe floppy after resume - it worked. Narrowing the 
> initialization code down resulted in this patch.

lol, OK.  I added this to the changelog:

  This fix resets the floppy controller on resume.  It was
  experimentally determined to bring the controller back to life - we
  don't really know why it works.

  floppy_init() does the same thing at boot/modprobe time.

Let's see how it goes...  If someone reports breakage then we can
always change the driver so that activation of your new code requires a
module parameter.