Re: [Bug #13663] suspend to ram regression (IDE related)

[Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>]

On Wednesday 01 July 2009 16:47:41 Wu Zhangjin wrote:
> On Wed, 2009-07-01 at 22:31 +0800, Jeff Chua wrote:
> > On Tue, Jun 30, 2009 at 12:21 AM, Jeff Chua<jeff.chua.linux@gmail.com> 
> > wrote:
> > 
> > > I just tried, and it "seems" to work. Will try a few more cycles.
> > 
> > STD/STR survived quite a few cycles now. Patch seems to be doing the
> > right thing.
> > 
> > On Mon, Jun 29, 2009 at 11:51 PM, Etienne
> > Basset<etienne.basset@numericable.fr> wrote:
> > 
> > > To have STR/resume work with current git, I have to :
> > 
> > > 1) apply Bart's patch
> > 
> > This is not yet in Linus's tree. And much needed to really fix the problem.
> > 
> > > 2) revert this commit : a1317f714af7aed60ddc182d0122477cbe36ee9b
> > 
> 
> Yes, This commit must be reverted, otherwise, STD/Hibernation will not
> work either. I have tested it on two different loongson-based machines:
> fuloong2e box and yeeloong2f netbook.(loongson is mips compatiable)

Since it seems like Dave is taking his sweet time with doing the revert
I stared at the code a bit more and I think that I finally found the bug
(thanks to your debugging work for giving me the right hint!).

The patch needs to take into the account a new code introduced by the recent
block layer changes (commit 8f6205cd572fece673da0255d74843680f67f879):

@@ -555,8 +560,11 @@ repeat:
                startstop = start_request(drive, rq);
                spin_lock_irq(&hwif->lock);
 
-               if (startstop == ide_stopped)
+               if (startstop == ide_stopped) {
+                       rq = hwif->rq;
+                       hwif->rq = NULL;
                        goto repeat;
+               }
        } else
                goto plug_device;
 out:

and not zero hwif->rq if the device is blocked. 

Could you try the attached patch and see if it fixes the issue?

[ Dave: while I appreciate fast handling of my patches I had strongly
  suggested giving this particular one some extra testing (because there
  were a lot of changes in between the time that it has been tested
  against other kernel subsystems).  Yet, it seems that its linux-next
  exposure was minimal at best..  :( ]

---
 drivers/ide/ide-io.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Index: b/drivers/ide/ide-io.c
===================================================================
--- a/drivers/ide/ide-io.c
+++ b/drivers/ide/ide-io.c
@@ -532,7 +532,8 @@ repeat:
 
                if (startstop == ide_stopped) {
                        rq = hwif->rq;
-                       hwif->rq = NULL;
+                       if ((drive->dev_flags & IDE_DFLAG_BLOCKED) == 0)
+                               hwif->rq = NULL;
                        goto repeat;
                }
        } else