Hi Jaehoon,
On 2016/5/27 8:53, Jaehoon Chung wrote:
Hi Shawn,
On 05/26/2016 12:08 PM, Shawn Lin wrote:
The main reason to add this check is to avoid unnecessary
mmc_request if the card is removed. Although we have already
check 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.
What's unnecessary mmc_request?
the on-going read/write/ and the corresponding sbc like cmd13, etc.
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@xxxxxxxxxxxxxx>
---
drivers/mmc/host/dw_mmc.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index cb30e91..2940d24 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)
@@ -1248,6 +1249,8 @@ static void dw_mci_request(struct mmc_host *mmc, struct mmc_request *mrq)
WARN_ON(slot->mrq);
+ dw_mci_get_cd(mmc);
+
If my understanding is right, it can be replaced
if (!test_bit(DW_MMC_CARD_PRESENT, &slot->flags))
to
if (!dw_mci_get_cd(mmc))
yeah~ It looks better.
Best Regards,
Jaehoon Chung
/*
* The check for card presence and queueing of the request must be
* atomic, otherwise the card could be removed in between and the
--
Best Regards
Shawn Lin
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