ACPI: fix Medion _PRT quirk (use "ISA_", not "ISA")

This fixes the builtin RTL8139 NIC on the Medion MD9580-F laptop.  The
BIOS reports the interrupt routing incorrectly.  I recently added a
quirk to work around this, and this patch fixes a typo in the quirk.

We pad every ACPI pathname component to four characters, so ".ISA." will
never match anything.  We need ".ISA_." instead.

Thank you Johann-Nikolaus Andreae <>
for patiently testing this patch.


Signed-off-by: Bjorn Helgaas <>
Signed-off-by: Linus Torvalds <>
diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c
index 7af414a..89022a7 100644
--- a/drivers/acpi/pci_irq.c
+++ b/drivers/acpi/pci_irq.c
@@ -131,8 +131,8 @@
 static struct prt_quirk prt_quirks[] = {
 	{ medion_md9580, 0, 0, 9, 'A',
-		"\\_SB_.PCI0.ISA.LNKA",
-		"\\_SB_.PCI0.ISA.LNKB"},
+		"\\_SB_.PCI0.ISA_.LNKA",
+		"\\_SB_.PCI0.ISA_.LNKB"},
 	{ dell_optiplex, 0, 0, 0xd, 'A',