On Jun 20, 2011, at 3:38 AM, Shawn Guo wrote: > The issue was initially found by Eric Benard as below. > > http://permalink.gmane.org/gmane.linux.ports.arm.kernel/108031 > > Not sure about other SDHCI based controller, but on Freescale eSDHC, > the SDHCI_INT_CARD_INSERT bits will be immediately set again when it > gets cleared, if a card is inserted. The driver need to mask the irq > to prevent interrupt storm which will freeze the system. And the > SDHCI_INT_CARD_REMOVE gets the same situation. > > The patch fixes the problem based on the initial idea from > Eric Benard. > > Signed-off-by: Shawn Guo <shawn.guo@xxxxxxxxxx> > Cc: Eric Benard <eric@xxxxxxxxxx> > --- > drivers/mmc/host/sdhci.c | 27 +++++++++++++++++++++++---- > 1 files changed, 23 insertions(+), 4 deletions(-) > > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c > index 91d9892..d94e2b4 100644 > --- a/drivers/mmc/host/sdhci.c > +++ b/drivers/mmc/host/sdhci.c > @@ -127,7 +127,9 @@ static void sdhci_mask_irqs(struct sdhci_host *host, u32 irqs) > > static void sdhci_set_card_detection(struct sdhci_host *host, bool enable) > { > - u32 irqs = SDHCI_INT_CARD_REMOVE | SDHCI_INT_CARD_INSERT; > + u32 present = sdhci_readl(host, SDHCI_PRESENT_STATE) & > + SDHCI_CARD_PRESENT; > + u32 irqs = present ? SDHCI_INT_CARD_REMOVE : SDHCI_INT_CARD_INSERT; > > if (host->quirks & SDHCI_QUIRK_BROKEN_CARD_DETECTION) > return; Accessing off chip registers is slow. It would be better to check for the quirk first and then read the present state register. eg u32 present; u32 irqs; > if (host->quirks & SDHCI_QUIRK_BROKEN_CARD_DETECTION) > return; > present = sdhci_readl(host, SDHCI_PRESENT_STATE) & > SDHCI_CARD_PRESENT; > irqs = present ? SDHCI_INT_CARD_REMOVE : SDHCI_INT_CARD_INSERT; Philip -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
