Subject: Re: Inserting wavelan card disrupts USB sound playback?
To: enami tsugutomo <email@example.com>
From: Jonathan Stone <jonathan@DSG.Stanford.EDU>
Date: 10/17/2000 09:26:54
In message <firstname.lastname@example.org>enami tsugutomo writes
>Jonathan Stone <jonathan@DSG.Stanford.EDU> writes:
>> Oh, I see. Thank you again. But in that case, there are other drivers
>> whose interrupt routine needs auditing, because they dont check for
>> IFF_RUNNING (e.g., dp8390_intr(), used by if_ne_pcmcia.c.)
>Usually, sc->sc_enabled and IFF_RUNNING almost syncs, so the problem
>won't appear unless interrupts aren't shared.
Yep. I ran into this on a laptop. After running the PCIbios fixups,
*all* PCI devices are on irq9. USB speakers generate an interrupt on
irq9 every 20 msec. So 50 times a second, any enabled interrupt
fuction would be called; that includes the pccard slots. That gives
good opportunity for triggering race conditions with shared interrupt.
>By the way, with wi driver, when IFF_RUNNING is set while sc_enabled
>is false? I believe IFF_RUNNING isn't set unless device is enabled.
The initial patch i tested just checked sc_enabled;
it seemed safer to just leave that check in.