+static void piix_iocfg_bit18_quirk(struct pci_dev *pdev)
+{
+ static const struct dmi_system_id sysids[] = {
+ {
+ /* Clevo M570U sets IOCFG bit 18 if the cdrom
+ * isn't used to boot the system which
+ * disables the channel.
+ */
+ .ident = "M570U",
+ .matches = {
+ DMI_MATCH(DMI_SYS_VENDOR, "Clevo Co."),
+ DMI_MATCH(DMI_PRODUCT_NAME, "M570U"),
+ },
+ },
+
+ { } /* terminate list */
+ };
+ u32 iocfg;
+
+ if (!dmi_check_system(sysids))
+ return;
+
+ /* The datasheet says that bit 18 is NOOP but certain systems
+ * seem to use it to disable a channel. Clear the bit on the
+ * affected systems.
+ */
+ pci_read_config_dword(pdev, PIIX_IOCFG, &iocfg);
+ if (iocfg & (1 << 18)) {
+ dev_printk(KERN_INFO, &pdev->dev,
+ "applying IOCFG bit18 quirk\n");
+ iocfg &= ~(1 << 18);
+ pci_write_config_dword(pdev, PIIX_IOCFG, iocfg);
+ }
+}
+