[PATCH 4.4 55/66] PCI: shpchp: Enable bridge bus mastering if MSI is enabled

Greg Kroah-Hartman
2017-09-24T20:36:09Z

From: Aleksandr Bezzubikov <zuban32s@gmail.com>

commit 48b79a14505349a29b3e20f03619ada9b33c4b17 upstream.

An SHPC may generate MSIs to notify software about slot or controller
events (SHPC spec r1.0, sec 4.7). A PCI device can only generate an MSI if
it has bus mastering enabled.

Enable bus mastering if the bridge contains an SHPC that uses MSI for event
notifications.

Signed-off-by: Aleksandr Bezzubikov <zuban32s@gmail.com>
[bhelgaas: changelog]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Marcel Apfelbaum <marcel@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/pci/hotplug/shpchp_hpc.c | 2 ++
1 file changed, 2 insertions(+)

--- a/drivers/pci/hotplug/shpchp_hpc.c
+++ b/drivers/pci/hotplug/shpchp_hpc.c
@@ -1062,6 +1062,8 @@ int shpc_init(struct controller *ctrl, s
if (rc) {
ctrl_info(ctrl, "Can't get msi for the hotplug controller\n");
ctrl_info(ctrl, "Use INTx for the hotplug controller\n");
+ } else {
+ pci_set_master(pdev);
}

rc = request_irq(ctrl->pci_dev->irq, shpc_isr, IRQF_SHARED,