[ALSA] cmipci: check that the legacy MIDI port works

Check that the UART_EN bit actually enabled the MPU-401 port.
Apparently, C-Media thinks that it is a good idea to be paranoid here.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

1 files changed, 7 insertions, 0 deletions

diff --git a/sound/pci/cmipci.c b/sound/pci/cmipci.c
index fdc4615ea0e7..9149d00d1ad5 100644
--- a/sound/pci/cmipci.c
+++ b/sound/pci/cmipci.c
@@ -3012,6 +3012,13 @@ static int __devinit snd_cmipci_create(struct snd_card *card, struct pci_dev *pc
                         snd_cmipci_write(cm, CM_REG_LEGACY_CTRL, val);
                         /* enable UART */
                         snd_cmipci_set_bit(cm, CM_REG_FUNCTRL1, CM_UART_EN);
+                        if (inb(iomidi + 1) == 0xff) {
+                                snd_printk(KERN_ERR "cannot enable MPU-401 port"
+                                           " at %#lx\n", iomidi);
+                                snd_cmipci_clear_bit(cm, CM_REG_FUNCTRL1,
+                                                     CM_UART_EN);
+                                iomidi = 0;
+                        }
                 }
         }