Re: RTL8139 Interrupt line blocked

From: Manfred Spraul (manfreds@colorfullife.com)
Date: Sat Jan 15 2000 - 09:25:08 EST


From: "Oleg Drokin" <green@ccssu.crimea.ua>
> After I started to use RTL8139 in 100 Mbit mode I started to get this
> under heavy traffic:

AFAICS, you can ignore these messages:

> eth3: RTL8139 Interrupt line blocked, status 4.
> eth3: RTL8139 Interrupt line blocked, status 4.

The driver uses a timer to recover from hung transceivers. The timer noticed
that the card has new packets pending, but that the interrupt is not (yet)
called. How many of these messages do you receive, and how many interrupt
arrive? (cat /proc/interrupts). It's possible that they are caused by the
latency between "hardware triggers the interrupt" and "driver has
acknowledged the interrupt"

> eth3: SMP simultaneous entry of an interrupt handler.
rtl8129() is running on both cpus: [i guess because]
* one cpu because the hardware interrupt arrived
* one cpu because the timer called the function.

I guess that "dev->interrupt" enforces the synchronization, but I don't
understand why "dev->interrupt" is reset to 0:
rtl8129_interrupt():
> [...]
> /* A lock to prevent simultaneous entry bug on Intel SMP machines.
*/
> if (test_and_set_bit(0, (void*)&dev->interrupt)) {
> printk(KERN_ERR"%s: SMP simultaneous entry of an interrupt
handler.\n",
> dev->name);
> dev->interrupt = 0; /* Avoid halting machine. */
> return;
> }

--
    Manfred

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