On Thu, Sep 13, 2012 at 12:01 PM, Hebbar, Gururaja
<gururaja.hebbar@xxxxxx> wrote:
> From: Vaibhav Bedia <vaibhav.bedia@xxxxxx>
>
> In some cases mmc_suspend_host() 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.
>
> ret = mmc_suspend_host(host->mmc);
> if (ret) {
> host->suspended = 0;
> if (host->pdata->resume) {
> ret = host->pdata->resume(dev, host->slot_id);
>
> The return status from mmc_suspend_host() is overwritten by return
> status from host->pdata->resume. So the original return status is lost.
>
> 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>
> Signed-off-by: Hebbar, Gururaja <gururaja.hebbar@xxxxxx>
This version is good.
Acked-by: Venkatraman S <svenkatr@xxxxxx>
> ---
> Changes from V1:
> - Instead of forcibly returning -EBUSY on err, retain old
> status and pass on the same to the caller.
> - add more detail to commit message (explanation with code
> snippet)
>
> :100644 100644 9afdd20... d9af5f1... M drivers/mmc/host/omap_hsmmc.c
> drivers/mmc/host/omap_hsmmc.c | 3 +--
> 1 files changed, 1 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
> index 9afdd20..d9af5f1 100644
> --- a/drivers/mmc/host/omap_hsmmc.c
> +++ b/drivers/mmc/host/omap_hsmmc.c
> @@ -2050,8 +2050,7 @@ static int omap_hsmmc_suspend(struct device *dev)
> if (ret) {
> host->suspended = 0;
> if (host->pdata->resume) {
> - ret = host->pdata->resume(dev, host->slot_id);
> - if (ret)
> + if (host->pdata->resume(dev, host->slot_id))
> dev_dbg(dev, "Unmask interrupt failed\n");
> }
> goto err;
> --
> 1.7.0.4
>
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