Re: can/sja1000: potential issue in sja1000.c?

[Marc Kleine-Budde <mkl@pengutronix.de>]

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On 02/10/2012 12:00 PM, Stephane Grosjean wrote:
> Hi all,
> 
> While always fighting against pcmcia Oliver (very hot) unplug issue, I
> decided to have a look to the sja1000 lib, since the pcmcia driver ISR
> does call "sja1000_interrupt()",
> 
> Unfortunately, I found that:
> 
>                 if (isrc & IRQ_RI) {
>                         /* receive interrupt */
>                         while (status & SR_RBS) {
>                                 sja1000_rx(dev);
>                                 status = priv->read_reg(priv, REG_SR);
>                         }
>                 }
> 
> My problem is, once the card is unplugged, every ioread in its
> corresponding io space does return 0xff...
> I just change this potential infinite while() into a corresponding
> for(;;) loop to test, like this:
> 
> -                        while (status & SR_RBS) {
> +                        int i;
> +                        for (i = 0; (status & SR_RBS) && (i < 10); i++) {
> 
> And no more PC hang!
> 
> Can you confirm this, please?
> 
> @Oliver: IMHO, the 0xff (invalid) value is also the reason of the
> "wakeup interrupt" message you got when unplugging the cards from their
> slots...

Is 0xff a valid value for REG_SR in the first place? If not we can for
example exit the interrupt handler.

Marc

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