Re: [patch] floppy: suspend/resume fix

Mikael Pettersson
2006-11-12T17:53:32Z

On Sun, 12 Nov 2006 16:47:12 +0100, Ingo Molnar wrote:
>* Mikael Pettersson <mikpe@it.uu.se> wrote:
>
>> On my old Dell Latitude laptop, the first access to the floppy after
>> having resumed from APM suspend fails miserably and generates these
>> kernel messages (from 2.6.19-rc5):
>[...]
>
>> It's only the first post-resume access that triggers this failure,
>> subsequent accesses do work.
>>
>> I've traced the cause to Ingo's lockdep patch in 2.6.18-rc1 (see
>> below): reverting it makes the floppy work after resume again.
>
>could you check the patch below? I had to add a platform driver to
>floppy.c to get suspend/resume callbacks, but otherwise it's relatively
>straightforward.

Sorry, no joy. The first access post-resume still fails and generates:

floppy0: disk absent or changed during operation
end_request: I/O error, dev fd0, sector 0
Buffer I/O error on device fd0, logical block 0
floppy0: disk absent or changed during operation
end_request: I/O error, dev fd0, sector 8
Buffer I/O error on device fd0, logical block 1
floppy0: disk absent or changed during operation
end_request: I/O error, dev fd0, sector 16
Buffer I/O error on device fd0, logical block 2
floppy0: disk absent or changed during operation
end_request: I/O error, dev fd0, sector 24
Buffer I/O error on device fd0, logical block 3
floppy0: disk absent or changed during operation
end_request: I/O error, dev fd0, sector 32
Buffer I/O error on device fd0, logical block 4
floppy0: disk absent or changed during operation
end_request: I/O error, dev fd0, sector 40
Buffer I/O error on device fd0, logical block 5
floppy0: disk absent or changed during operation
end_request: I/O error, dev fd0, sector 48
Buffer I/O error on device fd0, logical block 6
floppy0: disk absent or changed during operation
end_request: I/O error, dev fd0, sector 56
Buffer I/O error on device fd0, logical block 7
floppy0: disk absent or changed during operation
end_request: I/O error, dev fd0, sector 0
Buffer I/O error on device fd0, logical block 0

The 2nd etc post-resume accesses work like before.

Your patch did change the failure behaviour slightly.
Previously the first post-resume access would experience
a delay of about a second or so, and then report an error.
With this patch the error is immediate.

/Mikael

> Ingo
>
>----------------------->
>Subject: [patch] floppy: suspend/resume fix
>From: Ingo Molnar <mingo@elte.hu>
>
>introduce a floppy platform-driver and suspend/resume ops to
>stop/start the floppy driver. Bug reported by Mikael Pettersson.
>
>Signed-off-by: Ingo Molnar <mingo@elte.hu>
>---
> drivers/block/floppy.c | 31 ++++++++++++++++++++++++++++++-
> 1 file changed, 30 insertions(+), 1 deletion(-)
>
>Index: linux/drivers/block/floppy.c
>===================================================================
>--- linux.orig/drivers/block/floppy.c
>+++ linux/drivers/block/floppy.c
>@@ -4157,6 +4157,28 @@ static void floppy_device_release(struct
> complete(&device_release);
> }
>
>+static int floppy_suspend(struct platform_device *dev, pm_message_t state)
>+{
>+ floppy_release_irq_and_dma();
>+
>+ return 0;
>+}
>+
>+static int floppy_resume(struct platform_device *dev)
>+{
>+ floppy_grab_irq_and_dma();
>+
>+ return 0;
>+}
>+
>+static struct platform_driver floppy_driver = {
>+ .suspend = floppy_suspend,
>+ .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)
>@@ -4205,10 +4227,14 @@ static int __init floppy_init(void)
> 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);
>
>@@ -4352,6 +4378,8 @@ out_flush_work:
> 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:
>@@ -4543,6 +4571,7 @@ void cleanup_module(void)
> init_completion(&device_release);
> 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]);
>