[PATCH 3.16 016/133] PCI: shpchp: Enable bridge bus mastering if MSI is enabled

From: Ben Hutchings
Date: Tue Nov 21 2017 - 21:21:24 EST

3.16.51-rc1 review patch. If anyone has any objections, please let me know.


From: Aleksandr Bezzubikov <zuban32s@xxxxxxxxx>

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

Signed-off-by: Aleksandr Bezzubikov <zuban32s@xxxxxxxxx>
[bhelgaas: changelog]
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Reviewed-by: Marcel Apfelbaum <marcel@xxxxxxxxxx>
Acked-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
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
@@ -1061,6 +1061,8 @@ 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,