PCI PM: Make it possible to force using INTx for PCIe PME signaling
Apparently, some machines may have problems with PCI run-time power
management if MSIs are used for the native PCIe PME signaling. In
particular, on the MSI Wind U-100 PCIe PME interrupts are not
generated by a PCIe root port after a resume from suspend to RAM, if
the system wake-up was triggered by a PME from the device attached to
this port. [It doesn't help to free the interrupt on suspend and
request it back on resume, even if that is done along with disabling
the MSI and re-enabling it, respectively.] However, if INTx
interrupts are used for this purpose on the same machine, everything
works just fine.
For this reason, add a kernel command line switch allowing one to
request that MSIs be not used for the native PCIe PME signaling,
introduce a DMI table allowing us to blacklist machines that need
this switch to be set by default and put the MSI Wind U-100 into this
table.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/drivers/pci/pcie/portdrv_pci.c b/drivers/pci/pcie/portdrv_pci.c
index 13c8972..127e8f1 100644
--- a/drivers/pci/pcie/portdrv_pci.c
+++ b/drivers/pci/pcie/portdrv_pci.c
@@ -15,6 +15,7 @@
#include <linux/slab.h>
#include <linux/pcieport_if.h>
#include <linux/aer.h>
+#include <linux/dmi.h>
#include "portdrv.h"
#include "aer/aerdrv.h"
@@ -273,10 +274,36 @@
.driver.pm = PCIE_PORTDRV_PM_OPS,
};
+static int __init dmi_pcie_pme_disable_msi(const struct dmi_system_id *d)
+{
+ pr_notice("%s detected: will not use MSI for PCIe PME signaling\n",
+ d->ident);
+ pcie_pme_disable_msi();
+ return 0;
+}
+
+static struct dmi_system_id __initdata pcie_portdrv_dmi_table[] = {
+ /*
+ * Boxes that should not use MSI for PCIe PME signaling.
+ */
+ {
+ .callback = dmi_pcie_pme_disable_msi,
+ .ident = "MSI Wind U-100",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR,
+ "MICRO-STAR INTERNATIONAL CO., LTD"),
+ DMI_MATCH(DMI_PRODUCT_NAME, "U-100"),
+ },
+ },
+ {}
+};
+
static int __init pcie_portdrv_init(void)
{
int retval;
+ dmi_check_system(pcie_portdrv_dmi_table);
+
retval = pcie_port_bus_register();
if (retval) {
printk(KERN_WARNING "PCIE: bus_register error: %d\n", retval);