The FEC doesn't have a real interrupt status register, that takes into account the mask status of the IRQ. The driver reads the raw interrupt event register, which also reports events for masked IRQs. The driver needs to apply the current mask itself, to avoid acking IRQs that are currently masked, as NAPI relies on the masking to hide the IRQs. The current behavior of just acking all interrupts regardless of their mask status opens the driver up the "rotting packet" race-window, as described in the original NAPI-HOWTO, which has been observed in the wild. Signed-off-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx> --- drivers/net/ethernet/freescale/fec_main.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c index 01f7e811739b..498264969e89 100644 --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -1572,7 +1572,8 @@ fec_enet_interrupt(int irq, void *dev_id) uint int_events; irqreturn_t ret = IRQ_NONE; - int_events = readl(fep->hwp + FEC_IEVENT); + int_events = readl_relaxed(fep->hwp + FEC_IEVENT) & + readl_relaxed(fep->hwp + FEC_IMASK); writel(int_events, fep->hwp + FEC_IEVENT); fec_enet_collect_events(fep, int_events); -- 2.8.1 _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
