Re: [PATCH] Fix floppy hibernation

[Ondrej Zary <linux@rainbow-software.org>]

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