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

[Wolfgang Grandegger <wg@grandegger.com>]

On 02/10/2012 12:16 PM, Marc Kleine-Budde wrote:
> 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.

Is the access to the address space of an unplugged card defined at all?
Or may it even hang the system?

Wolfgang.