On Thu, Mar 22, 2012 at 19:57:16, S, Venkatraman wrote: > 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 ? As seen from http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=drivers/mmc/host/omap_hsmmc.c;h=fd0c661bbad38a7152a37955146ff6068d4d7137;hb=refs/tags/v3.3 omap_hsmmc.c @ 2045 pdata->resume = omap_hsmmc_resume_cdirq; @227 static int omap_hsmmc_resume_cdirq(struct device *dev, int slot) { struct omap_mmc_platform_data *mmc = dev->platform_data; enable_irq(mmc->slots[0].card_detect_irq); return 0; -----> always return 0 } @2167 if (host->pdata->resume) { ret = host->pdata->resume(&pdev->dev, --> ret becomes zero irrespective of its previous value. host->slot_id); if (ret) dev_dbg(mmc_dev(host->mmc), "Unmask interrupt failed\n"); } > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > Regards, Gururaja -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
