I've been working on the staging slicoss driver (for an ethernet NIC). I haven't been able to find any detailed documentation about the card online, all I have is the source code. During the PCI probe routine slic_entry_probe(), the driver attempts to load some configuration data from the card. The driver disables interrupts from the deviece and polls the ISR which signals the completed transfer. The relevant code is in drivers/staging/slicoss/slicoss.c:slic_card_init: [...] slic_config_get(adapter, phys_configl, phys_configh); for (;;) { if (adapter->pshmem->isr) { [...] } else { mdelay(1); i++; if (i > 5000) { dev_err(&adapter->pcidev->dev, "%d config data fetch timed out!\n", adapter->port); [...] } } } [...] The only problem is, this times out more than half the time. And when it succeeds, it [seemingly] always takes 22 cycles. I have tried increasing 5000 to various higher numbers (up to 50000) with no effect. I thought it might be a compiler optimization or coherence issue so I threw a mb() in the loop and that seemed to have no effect as well. Any recommendations on debugging? Thanks. --David