On Mon, Feb 10, 2014 at 11:31:40AM +0800, Dong Aisheng wrote:
> On Sun, Feb 9, 2014 at 11:14 PM, Russell King - ARM Linux
> <linux@xxxxxxxxxxxxxxxx> wrote:
> > Okay, I have this working now - there was a hardware problem. However,
> > it's obvious that this has never been tested with lockdep enabled beacuse
> > of the following:
> >
> > disable_irq(host->irq);
> > spin_lock(&host->lock);
> > host->mrq = &mrq;
> >
> > sdhci_send_command(host, mrq.cmd);
> >
> > spin_unlock(&host->lock);
> > enable_irq(host->irq);
> >
> > You can't "work around" stuff like this. Use spin_lock_irq()..
> > spin_unlock_irq(). You can't just disable the interrupt line and
> > expect lockdep to know that it's safe.
> >
>
> Yes, i missed this.
> Such kind of code was originally referenced from sdhci_execute_tuning.
> It was formerly fixed in commit 2b35bd83.
> But i did miss sdhci-esdhci-imx also has such issue.
> Thanks for the reminder.
>
> You can try the following fix and I will send out a patch for it later.
> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c
> b/drivers/mmc/host/sdhci-esdhc-imx.c
> index b841bb7..0372baf 100644
> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> @@ -720,6 +720,7 @@ static int esdhc_send_tuning_cmd(struct sdhci_host
> *host, u32 opcode)
> struct mmc_data data = {0};
> struct scatterlist sg;
> char tuning_pattern[ESDHC_TUNING_BLOCK_PATTERN_LEN];
> + unsigned long flags;
>
> cmd.opcode = opcode;
> cmd.arg = 0;
> @@ -742,14 +743,12 @@ static int esdhc_send_tuning_cmd(struct
> sdhci_host *host, u32 opcode)
> mrq.done = esdhc_request_done;
> init_completion(&(mrq.completion));
>
> - disable_irq(host->irq);
> - spin_lock(&host->lock);
> + spin_lock_irqsave(&host->lock, flags);
> host->mrq = &mrq;
>
> sdhci_send_command(host, mrq.cmd);
>
> - spin_unlock(&host->lock);
> - enable_irq(host->irq);
> + spin_unlock_irqrestore(&host->lock, flags);
>
> wait_for_completion(&mrq.completion);
You don't need to use irqsave/irqrestore here - IRQs must be enabled here
otherwise wait_for_completion() will scream - scheduling with interrupts
disabled is not allowed.
--
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in database were 13.1 to 19Mbit for a good line, about 7.5+ for a bad.
Estimate before purchase was "up to 13.2Mbit".
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