On Thu, Mar 22, 2012 at 6:50 PM, Bedia, Vaibhav <vaibhav.bedia@xxxxxx> wrote: > On Thu, Mar 22, 2012 at 09:53:23, Bedia, Vaibhav wrote: >> Hi, >> >> I am trying to do suspend-resume test with a file copy on MMC/SD going on >> in the background. The test involves simply copying a 450MB file on an ext3 >> partition to the same partition under a different name. >> >> This is on an AM335x board which uses the omap_hsmmc driver. >> The kernel is v3.2 and I have also applied the following patch >> > > [...] > > I found that whenever this issue crops up, mmc_host_suspend() is not able to claim the host > And returns -EBUSY. omap_hsmmc driver does not pass on this error code to the PM core and > hence the suspend process continues. When the driver is made to return -EBUSY, the suspend > process gets aborted and the user can try suspending again. I am not sure whether this sort > of suspend failure is acceptable or the driver is doing something wrong. The following > workaround is what I came up with. Do this look a reasonable thing to do? > > --- > > From a4040dd1869b351a5fa29dacd08facf6e24df609 Mon Sep 17 00:00:00 2001 > From: Vaibhav Bedia <vaibhav.bedia@xxxxxx> > Date: Thu, 22 Mar 2012 17:14:49 +0530 > Subject: [PATCH 1/1] mmc: omap_hsmmc: Pass on the suspend failure to the PM core > > In some cases mmc_host_suspend() is not able to claim the > host and proceed with the suspend process. The core returns > -EBUSY to the host controller driver. Unfortunately, the > host controller driver does not pass on this information > to the PM core and hence the system suspend process continues. > > In these cases the MMC core gets to an unexpected state > during resume and multiple issues related to MMC crop up. > 1. Host controller driver starts accessing the device registers > before the clocks are enabled which leads to a prefetch abort. > 2. A file copy thread which was launched before suspend gets > stuck due to the host not being reclaimed during resume. > > To avoid such problems pass on the -EBUSY status to the PM core > from the host controller driver. With this change, MMC core > suspend might still fail but it does not end up making the > system unusable. Suspend gets aborted and the user can try > suspending the system again. > > Signed-off-by: Vaibhav Bedia <vaibhav.bedia@xxxxxx> > --- > drivers/mmc/host/omap_hsmmc.c | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c > index 3d8dbbb..1f938d9 100644 > --- a/drivers/mmc/host/omap_hsmmc.c > +++ b/drivers/mmc/host/omap_hsmmc.c > @@ -2238,6 +2238,7 @@ static int omap_hsmmc_suspend(struct device *dev) > dev_dbg(mmc_dev(host->mmc), > "Unmask interrupt failed\n"); > } > + ret = -EBUSY; > goto err; > } > > -- > 1.7.0.4 I see (in 3.3) that the host controller driver does a "return ret" and that means the errors is propagated. Where is the return code lost /overridden ? -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
