If a hotplug port is suspended to D3cold, its slot status register cannot be read. If that hotplug port happens to share its IRQ with other devices, then whenever an interrupt occurs for one of these devices, a "no response from device" message is logged with level KERN_INFO. Apart from this annoyance, CPU time is needlessly spent trying to read the slot status register even though we know in advance that it will fail. On MacBook Pros introduced 2011 and 2012, the IRQ of a Thunderbolt hotplug port is unfortunately shared with a wireless card, an audio card and an SDXC controller. When the Thunderbolt controller is powered down, the machine carries out at least one unneeded slot status register read for each wireless packet received and prints a corresponding error message to the system log. The hotplug port's current_state will be D3cold when it's powered down, so ignore interrupts that occur during that power state. Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx> --- drivers/pci/hotplug/pciehp_hpc.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index 5c24e93..08e84d6 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -546,6 +546,10 @@ static irqreturn_t pcie_isr(int irq, void *dev_id) u8 present; bool link; + /* Interrupts cannot originate from a controller that's asleep */ + if (pdev->current_state == PCI_D3cold) + return IRQ_NONE; + /* * In order to guarantee that all interrupt events are * serviced, we need to re-inspect Slot Status register after -- 2.8.1 -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
