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SubjectRe: [PATCH v2 2/2] mmc: dw_mmc: check card present before starting request
Hi Shawn,

On 05/27/2016 03:37 PM, Shawn Lin wrote:
> The main reason to add this check is to avoid unnecessary
> mmc_request like the on-going cmd and the corresponding sbc
> if the card is removed. Although we have already checked this in
> dw_mci_handle_cd for runtime usage of sd card and dw_mci_init_slot
> for noremovable devices, but there is a timing gap before it really
> calls dw_mci_get_cd as mmc_detect_change needs some delay here.
>
> Another gain here is that we could save some checkings of card status
> after sd card been removed.
>
> Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>

Applied on my repository.
Thanks!

Best Regards,
Jaehoon Chung

>
> ---
>
> Changes in v2:
> - hold lock before dw_mci_queue_request
>
> drivers/mmc/host/dw_mmc.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index cb30e91..2b4b3df 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -105,6 +105,7 @@ struct idmac_desc {
> static bool dw_mci_reset(struct dw_mci *host);
> static bool dw_mci_ctrl_reset(struct dw_mci *host, u32 reset);
> static int dw_mci_card_busy(struct mmc_host *mmc);
> +static int dw_mci_get_cd(struct mmc_host *mmc);
>
> #if defined(CONFIG_DEBUG_FS)
> static int dw_mci_req_show(struct seq_file *s, void *v)
> @@ -1253,15 +1254,15 @@ static void dw_mci_request(struct mmc_host *mmc, struct mmc_request *mrq)
> * atomic, otherwise the card could be removed in between and the
> * request wouldn't fail until another card was inserted.
> */
> - spin_lock_bh(&host->lock);
>
> - if (!test_bit(DW_MMC_CARD_PRESENT, &slot->flags)) {
> - spin_unlock_bh(&host->lock);
> + if (!dw_mci_get_cd(mmc)) {
> mrq->cmd->error = -ENOMEDIUM;
> mmc_request_done(mmc, mrq);
> return;
> }
>
> + spin_lock_bh(&host->lock);
> +
> dw_mci_queue_request(host, slot, mrq);
>
> spin_unlock_bh(&host->lock);
>

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