On 12 December 2017 at 11:49, Daniel Drake <drake@xxxxxxxxxxxx> wrote:
> The Weibu F3C MiniPC has an onboard AP6255 module, presenting
> two SDIO functions on a single MMC host (Bluetooth/btsdio and
> WiFi/brcmfmac), and the mmc layer correctly detects this as
> non-removable.
>
> After suspend/resume, the wifi and bluetooth interfaces disappear
> and do not get probed again.
>
> The conditions here are:
>
> 1. During suspend, we reach mmc_pm_notify()
>
> 2. mmc_pm_notify() calls mmc_sdio_pre_suspend() to see if we can
> suspend the SDIO host. However, mmc_sdio_pre_suspend() returns
> -ENOSYS because btsdio_driver does not have a suspend method.
>
> 3. mmc_pm_notify() proceeds to remove the card
>
> 4. Upon resume, mmc_rescan() does nothing with this host, because of
> the rescan_entered check which aims to only scan a non-removable
> device a single time (i.e. during boot).
>
> Fix the loss of functionality by detecting that we are unable to
> suspend a non-removable host, so avoid the forced removal in that
> case. The comment above this function already indicates that this
> code was only intended for removable devices.
>
> Signed-off-by: Daniel Drake <drake@xxxxxxxxxxxx>
Thanks, applied for next!
Kind regards
Uffe
> ---
> drivers/mmc/core/core.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> Replaces previous approach:
> [PATCH] mmc: allow rescan of non-removable hosts on resume
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 26431267a3e2..6f815a264285 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -2763,6 +2763,14 @@ static int mmc_pm_notify(struct notifier_block *notify_block,
> if (!err)
> break;
>
> + if (!mmc_card_is_removable(host)) {
> + dev_warn(mmc_dev(host),
> + "pre_suspend failed for non-removable host: "
> + "%d\n", err);
> + /* Avoid removing non-removable hosts */
> + break;
> + }
> +
> /* Calling bus_ops->remove() with a claimed host can deadlock */
> host->bus_ops->remove(host);
> mmc_claim_host(host);
> --
> 2.14.1
>
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