ALSA: cmipci: Allow disabling MPU port via module option (d8cac620) · Commits · 戴 / test

Patrick May reported that his sound card with CMI8378 chip causes a crash / reboot when accessing the MIDI port that isn't actually present on the board. Moreover, despite of the documentation, passing mpu_port=0 doesn't disable the MIDI port on this board. It implies that the chip is a newer revision and the MPU401 port is integrated and mapped on the PCI register. For this chip model, the driver enables the MPU port unconditionally, so far. Although fixing the unexpected reboot would be the best solution, it's not so trivial to identify the cause. So, as a plan B, this patch extends the existing mpu_port option usage to allow disabling the port by specifying the value 0, just like we applied for fm_port option in commit ("[ALSA] cmipci - Allow to disable integrated FM port"). As default, the MPU port is still enabled, but user can pass mpu_port=0 to disable it. Reported-and-tested-by:

Patrick May <dusthillresident@gmail.com> Link: https://lore.kernel.org/r/20191217081448.1144-1-tiwai@suse.de Signed-off-by:

Takashi Iwai <tiwai@suse.de>

Documentation/sound/alsa-configuration.rst

+2 −1

Original line number	Diff line number	Diff line
		@@ -495,7 +495,8 @@ Module for C-Media CMI8338/8738/8768/8770 PCI sound cards.
		mpu_port
		port address of MIDI interface (8338 only):
		0x300,0x310,0x320,0x330 = legacy port,
		0 = disable (default)
		1 = integrated PCI port (default on 8738),
		0 = disable
		fm_port
		port address of OPL-3 FM synthesizer (8x38 only):
		0x388 = legacy port,

sound/pci/cmipci.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -42,7 +42,7 @@ MODULE_SUPPORTED_DEVICE("{{C-Media,CMI8738},"
		static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX; /* Index 0-MAX */
		static char id[SNDRV_CARDS] = SNDRV_DEFAULT_STR; / ID for this card */
		static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP; /* Enable switches */
		static long mpu_port[SNDRV_CARDS];
		static long mpu_port[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS-1)] = 1};
		static long fm_port[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS-1)]=1};
		static bool soft_ac3[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS-1)]=1};
		#ifdef SUPPORT_JOYSTICK
		@@ -3132,6 +3132,7 @@ static int snd_cmipci_create(struct snd_card card, struct pci_dev pci,
		if (cm->chip_version >= 39) {
		val = snd_cmipci_read_b(cm, CM_REG_MPU_PCI + 1);
		if (val != 0x00 && val != 0xff) {
		if (mpu_port[dev])
		iomidi = cm->iobase + CM_REG_MPU_PCI;
		integrated_midi = 1;
		}

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