linux-kernel - Re: [PATCH] mmc: sdhci: Avoid needless loop while handling SDIO interrupts in sdhci

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Date:	Tue, 26 Nov 2013 17:12:18 -0500
From:	Chris Ball <cjb@...top.org>
To:	Alexey Neyman <stilor@....net>
Cc:	Dong Aisheng <dongas86@...il.com>,
	linux-mmc@...r.kernel.org (open list:SECURE DIGITAL HO...),
	linux-kernel@...r.kernel.org (open list)
Subject: Re: [PATCH] mmc: sdhci: Avoid needless loop while handling SDIO interrupts in sdhci_irq()

Hi Alexey,

On Tue, Nov 05 2013, Alexey Neyman wrote:
> Ignore Card Interrupt bit in the interrupt status if we already know that
> mmc_signal_sdio_irq() is going to be called at the end of sdhci_irq(). This
> avoids a needless loop in sdhci_irq() repeatedly reading interrupt status
> and doing nothing.
>
> Signed-off-by: Alexey Neyman <stilor@....net>
> Acked-by: Dong Aisheng <b29396@...escale.com>
> ---
>  drivers/mmc/host/sdhci.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 7a7fb4f..a83cd1b 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2491,6 +2491,14 @@ again:
>  	result = IRQ_HANDLED;
>  
>  	intmask = sdhci_readl(host, SDHCI_INT_STATUS);
> +
> +	/*
> +	 * If we know we'll call the driver to signal SDIO IRQ, disregard
> +	 * further indications of Card Interrupt in the status to avoid a
> +	 * needless loop.
> +	 */
> +	if (cardint)
> +		intmask &= ~SDHCI_INT_CARD_INT;
>  	if (intmask && --max_loops)
>  		goto again;
>  out:

Thanks, this was included in 3.13-rc1 via mmc-next.

- Chris.
-- 
Chris Ball   <cjb@...top.org>   <http://printf.net/>
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